Answer:
she rode for 166.66 seconds , which is about 2 minutes and 47 seconds
Explanation:
We use the kinematic equation that relates initial and final velocities with time and distance travelled that is shown below:
[tex]distance=\frac{(v_i+v_f)*t}{2}[/tex]
which in our case gives:
[tex]distance=\frac{(v_i+v_f)*t}{2}\\500=\frac{(0+6)*t}{2}\\500=3*t\\t=\frac{500}{3} \,s\\t\approx 166.66\,sec[/tex]
which reduced to minutes gives 2 minutes and approximately 47 seconds
How much power is used if an athlete lifts a 50N weight up 2 meters in 10 seconds?
Answer:
the power used by the person is 10 W.
Explanation:
Given;
weight lifted, W = 50 N
distance through which the weight was lifted, d = 2 m
time of motion, t = 10 s
The power used by the person is calculated as;
[tex]P= FV\\\\P = F \ \times \ \frac{d}{t} \\\\P = 50 \ \times \ \frac{2}{10} \\\\P = 10 \ W[/tex]
Therefore, the power used by the person is 10 W.
Two point charges, Q1 and Q2, are separated by a distance R. If the magnitudes of both charges are tripled and their separation is also tripled, what happens to the electrical force that each charge exerts on the other one
Answer:
Remains the same
Explanation:
Kraig pulls a box to the right at an angle of 40 degrees to the horizontal with a force of 30 Newtons. If Kraig pulls the box a distance of 20 meters, determine the work done by Kraig.
Answer:
459.6J
Explanation:
Given parameters:
Angle of pull = 40°
Force applied = 30N
Distance moved = 20m
Unknown:
Work done by Kraig = ?
Solution:
To solve this problem;
Work done = F x dcosФ
d is the distance
F is the force
Ф is the angle given
Work done = 30 x 20cos40° = 459.6J
Burning can be:
controlled for useful work
stopped for use work
wasted for useful work
Answer:
Controlled for useful work
Explanation:
Here we want to select the option that best describes what burning can be used for
Generally, when we talk about something being burnt, we are referring to the fact that we have the thing being on fire.
So basically, when something is on fire, we can say it is burning. We can harness the burning strength of a particular material or substance to do useful work.
For example, in a fire place in our homes, the burning of wood pieces can be used to heat up our homes. It is this same wood burning that has devastating effects in the bushes which in fact when left uncontrolled can cause degrees of catastrophic damages.
But, by taking the pieces and placing in a fire place in our homes, we have successfully controlled its bad effect and use it to do the useful work of heating up the environment
Which of the following temperature readings is the coldest?
Group of answer choices
O 0F
O 0C
O K
Answer: K
Explanation:
From the temperature readings given, we should note that 0°F is thesame as 32°C. Therefore, 0°C is colder than 0°F.
We should note that at 0K which is written as K, it is the coolest and it is often called the absolute zero because at this degree, there can't be anything that's colder.
Therefore, the answer is K
Explain how this increases their efficiency. Explain how this increases their efficiency. Antireflective coating causes the phase shift of the light on the interface between the air and the panel increasing the path length of the light, so the solar panel turn more light into the energy. Antireflective coating decreases the index of refraction of the solar panel, so the losses of light caused by the refraction in the panel decreases, and the efficiency of the panel increases. Antireflective coating cancels the reflection of light from the panel, so the greater part of light enters the solar panel and can be turned into the energy. Antireflective coating refracts the light falling on the panel so the light of different wavelengths falls onto the different places of the solar panel and turns into energy with increased efficiency.
Answer:
c) True. If the coating cancels the light requested by the reflection, so there is more energy to enter the cell and therefore its efficiency increases
Explanation:
This exercise asks to analyze the effect of the antireflective coating on the efficiency of solar cells.
Let's start by expressing the expression for the interference of two light beams taken at when
* the phase change introduced when passing from air to 180º film
* the wavelength change by the refractive index of the film ln = lo / n
therefore the expression for destructive interference is
2 n t = m λ
where m is an integer
with these concepts we can analyze the different statements
a) False. Phase shift does not change the wavelength of light
b) False. The refractive index of the solar cell is not affected by the refractive index of the film since the two materials do not mix.
c) True. If the coating cancels the light requested by the reflection, so there is more energy to enter the cell and therefore its efficiency increases
d) false. In solar cells the incidence is almost normal, therefore the effect of refraction (separation of colors for different angles) is very small
A ball starts at rest and rolls down an inclined plane. The ball reaches 7.5 m/s in 3 seconds. What is the acceleration?
Answer:
[tex]a=2.5\ m/s^2[/tex]
Explanation:
Motion With Constant Acceleration
It's a type of motion in which the velocity of an object changes uniformly over time.
The equation that describes the change of velocities is:
[tex]v_f=v_o+at[/tex]
Where:
a = acceleration
vo = initial speed
vf = final speed
t = time
Solving the equation for a:
[tex]\displaystyle a=\frac{v_f-v_o}{t}[/tex]
The ball starts at rest (vo=0) and rolls down an inclined plane that makes it reach a speed of vf=7.5 m/s in t=3 seconds.
The acceleration is:
[tex]\displaystyle a=\frac{7.5-0}{3}[/tex]
[tex]\boxed{a=2.5\ m/s^2}[/tex]
The net electric flux through a cubic box with sides that are 22.0 cm long is 4950 N⋅m2/C . What charge is enclosed by the box?
Answer:
[tex]Q_{net}=4.38\,\,10^{-8}\,C[/tex]
Explanation:
We use Gauss's Law for the flux over a closed surface equal the net charge inside the closed surface divided the permitivity of space [tex]\epsilon_0=8.85\,\,10^{-12}\,\,\frac{C^2}{N*m^2}[/tex]
Therefore, by knowing the flux, we can estimate the net charge inside the cubic box with the product:
[tex]\Phi=\frac{Q_{net}}{\epsilon_0} \\Q_{net}=4950\,*\,8.85\,\,10^{-12} \,\,C\\Q_{net}=4.38\,\,10^{-8}\,C[/tex]
A potato gun is fired horizontally from a height of 1.5 meters with the potato launched at 25 m/s What is the time of flight of the potato?
Answer:
0.55 s
Explanation:
From the question given above, the following data were obtained:
Height (h) = 1.5 m
Horizontal velocity (v) = 25 m/s
Time of flight (t) =?
The time of flight of the potato talks about the total time spent by the potato in the air i.e the time taken for the potato to get to the ground..
Thus, we can obtain the time of flight of the potato as illustrated below:
Height (h) = 1.5 m
Acceleration due to gravity (g) = 9.8 m/s²
Time of flight (t) =?
H = ½gt²
1.5 = ½ × 9.8 × t²
1.5 = 4.9 × t²
Divide both side by 4.9
t² = 1.5 / 4.9
Take the square root of both side
t = √(1.5 / 4.9)
t = 0.55 s
Thus, the time of flight is 0.55 s
What is the impulse of a baseball thrown with a force of 75 N when in contact with the pitcher's
hand for 0.050 seconds?
Answer:
3.75Ns
Explanation:
Given data
F= 75N
time= 0.05seconds
We know that
P=Ft
substitute
P=75*0.05
P=3.75Ns
A billiard ball is moving in the x-direction at 30.0 cm/s and strikes another billiard ball moving in the y-direction at 40.0 cm/s. As a result of the collision, the first ball moves at 50.0 cm/s, and the second ball stops. In what final direction does the first ball move?
Answer:
53.13 °
Explanation:
In order to do this, we just need to apply the following:
tanα = Dy/Dx
Where:
Vy: speed of the ball in the y axis.
Vx: speed of the ball in the x axis.
At this point we do not need the speed of the first ball after the collision because in that moment is already heading in the direction that we are looking for. Therefore, we just need to use the innitial data to calculate the direction which the first ball will go.
According to this, then:
tanα = (40/30)
tanα = 1.3333
α = tan⁻¹(1.3333)
α = 53.13°This means that the final direction of the first ball is 53.13° and in the x axis because the starting momentum of this ball in the x axis has not dissapeared.
Hope this helps
On a day when the wind is blowing toward the south at 4 m/s, a runner jogs east at 5 m/s. What is the velocity (speed and direction) of the air relative to the runner
Answer:
[tex]v=5m/s[/tex]
Direction:SW(south-west)
Explanation:
From the question we are told that
Velocity and direction of Runner [tex]V_r= 5m/s ,East[/tex]
Velocity and direction of Air[tex]V_a= 4m/s ,South[/tex]
Generally the the resultant velocity v is mathematically given as
[tex]v=\sqrt{V_a^2+V_r^2}[/tex]
[tex]v=\sqrt{4^2+5^2}[/tex]
[tex]v=5m/s[/tex]
The resultant velocity is towards the south-west
name a type of relationship between current and potental difference for a resistor at constant temperature
Answer:
The current flowing through a resistor at a constant temperature is directly proportional to the potential difference across it. ... This is called Ohm's law.
Explanation:
I Looked It Up. So It May Be Wrong But I Hope This Helps!
Answer:
The current flowing through a resistor at a constant temperature is directly proportional to the potential difference across it. ... This is called Ohm's law.
A 50 kg girl rides on a 4.9 kg skateboard. The girl on the skateboard moves at 2.1 m/s. If the girl jumps off the skateboard backward with a velocity of 0.6 m/s, how fast does the skateboard roll away? ANSWER ASAP
Answer:
The skateboard rolls away at 29.7 m/s
Explanation:
Law Of Conservation Of Linear Momentum
It states the total momentum of a system of bodies is conserved unless an external force is applied to it. The formula for the momentum of a body with mass m and speed v is
P=mv.
If we have a system of bodies, then the total momentum is the sum of the individual momentums:
[tex]P=m_1v_1+m_2v_2[/tex]
If a collision occurs and the velocities change to v', the final momentum is:
[tex]P'=m_1v'_1+m_2v'_2[/tex]
Since the total momentum is conserved, then:
P = P'
[tex]m_1v_1+m_2v_2=m_1v'_1+m_2v'_2\qquad\qquad[1][/tex]
A girl of m1=50 kg rides an m2=4.9 kg skateboard and the common speed is v1=v2=2.1 m/s.
The girl jumps off the skateboard backward with a speed of v1'=-0.6 m/s (negative because it's opposite to the original direction). It's required to find the final speed of the skateboard. It will be calculated by solving for v2':
[tex]\displaystyle v'_2=\frac{m_1v_1+m_2v_2-m_1v'_1}{m_2}[/tex]
[tex]\displaystyle v'_2=\frac{50*2.1+4.9*2.1-50*(-0.6)}{4.9}[/tex]
Calculating:
[tex]\displaystyle v'_2=\frac{145.29}{4.9}=29.7\ m/s[/tex]
The skateboard rolls away at 29.7 m/s
Find the period of a pendulum that has a length of .6m and is on earth. Make sure that you show your work and prominently display the equation that you use to solve it.
Answer:
The period of this pendulum is [tex]T=1.55\: s[/tex]
Explanation:
The equation of motion of a pendulum is given by:
[tex]\frac{d\theta^{2}}{dt^{2}}+\frac{g}{L}sin(\theta)=0[/tex] (1)
Where:
θ is the angle of motion
g is the gravity at the earth surface (9.81 m/s²)
L is the length of the pendulum (0.6 m)
Now, using equation (1) we can find the square angular frequency (ω), it will be:
[tex]\omega^{2}=\frac{g}{L}[/tex]
[tex]\omega=\sqrt{\frac{g}{L}}[/tex]
Let's recall that the angular frequency is [tex]\omega=\frac{2\pi}{T}[/tex], then the period will be:
[tex]T=\frac{2\pi}{\omega}[/tex]
[tex]T={2\pi}\sqrt{\frac{L}{g}[/tex]
[tex]T=2\pi}\sqrt{\frac{0.6}{9.81}[/tex]
Therefore, the period of this pendulum is [tex]T=1.55\: s[/tex]
I hope it helps you!
Steve has a mass of 78 kg and is standing still on very slippery ice while holding a 2.5 kg can of peas. Steve throws the can to the right so that it travels with a velocity of 8.7 m/s. What is Steve’s velocity after he throws the can?
Which car has the most kinetic energy?
O 25 kg car driving at 30 kph
O 50 kg car driving at 30 kph
O 25 kg car driving at 60 kph
O 50 kg car driving at 60 kph
The voltage across a 5-uF capacitor is: v (t )equals 10 cos open parentheses 6000 t close parentheses space straight V. What is the current through this capacitor?
Answer:
- 0.3sin6000t A
Explanation:
Voltage, v = 10 cos 6000t V
Capacitance = 5-uF
Current flowing through, i(t)
i(t) = c * d/dt (V)
c = 5-uF = 5 * 10^-6 F
i(t) = (5 * 10^-6) * d/dt(10 cos 6000t)
d/dt(10 cos 6000t) = (10 * 6000) * (-sin 6000t)
Hence,
i(t) = (5*10^-6) * (10*6000) * (-sin 6000t)
i(t) = 5*10^-6 * 6*10^4 * - sin6000t
i(t) = 30 * 10^-2 * - sin6000t
i(t) = 0.3*-sin6000t
i(t) = - 0.3sin6000t Ampere
What do light waves NOT do when intereacting with matter
A. Absorbed
B. Reflected
C. Transmitted
D. Dissolve
Answer:
D. Dissolve
Explanation:
A light wave is not a soluble substance, so it cannot dissolve. But it can totally do A, B, and C.
To ____________________ something is to slowly mix in a bit of _____________ ___________________ with eggs or cream to raise the temperature slowly. This prevents the cream from curdling (turning lumpy and gross) or the eggs from scrambling in your sauce.
Answer:
temper; hot sauce
Explanation:
The context clue here is "raise the temperature slowly" gives a quick clue to temper (as a verb). The 4th definition of temper (as a verb) is "to bring to a suitable state by mixing or adding a usually liquid ingredient." Knowning, this leads to the second blank being hot sauce, as that's a liquid.
Choose all the answers that apply.
Connective tissue
D covers the outside of an organism
hold organs and other tissue in place
lines the inside of holow organs
D cushions the body and stores energy
attaches muscle to bone
joins bones together
Answer:
1. hold organs and other tissue in place
2. Attaches muscles to bone
Explanation:
From its name, the connective tissue has one of its most important functions to be the connection of tissues and organs.
They offer support and connection to other tissues such as tendons that attaches muscles to bones and also skeletons which offers support to the positions of the body.
Connective tissue also offer protection in various forms such as fibrous capsules and also bones that gives protection to delicate organs of the body
Heat naturally flows from an object that has a _______________ temperature to an object that has a _______________ temperature. Heat can be made to flow in the reverse direction if _______________ is done. A machine can never have an efficiency of _______________. This means that heat energy can never be fully converted into _______________ energy.
Answer:
higher, lower, external work, 100 %, work.
Explanation:
These paragraphs refer to the second law of thermodynamics. There are two statements for the second law of thermodynamics. They are as follows:
KELVIN STATEMENT:
All the heat from a source can never be transferred to the sink without the rejection of some heat.
CLAUSIUS STATEMENT:
Heat can not be transferred from a colder body to a hotter body without the application of som external work.
According to the statements the blanks can be filled as follows:
Heat naturally flows from an object that has a higher temperature to an object that has a Lower temperature. Heat can be made to flow in the reverse direction if external work is done. A machine can never have an efficiency of 100 %. This means that heat energy can never be fully converted into work energy.
Answer:
Heat naturally flows from an object that has a ______high_________ temperature to an object that has a ______lower_________ temperature. Heat can be made to flow in the reverse direction if _______work________ is done. A machine can never have an efficiency of ______100%_________. This means that heat energy can never be fully converted into _______mechanical energy________ energy.
Explanation: This is all derived from the Principles of the Second Law of Thermodynamics.
A 2.1-F capacitor is fully charged by a 6.0-V battery. The battery is then disconnected. The capacitor is not ideal and the charge slowly leaks out from the plates. The next day, the capacitor has lost half its stored energy. Calculate the amount of charge lost.
Answer:
6.3 C
Explanation:
From the question,
Energy lost by the capacitor(half it stored energy) = 1/4CV².......................... Equation 1
Where C = Capacitance of the capacitor, V = Volatge across the parallel plate of the capacitor.
E = 1/4CV²
Given: C = 2.1 F, V = 6.0 V
Substitute these values into equation 1
E = 1/4(2.1)(6²)
E = 18.9 J
But,
E = 1/2QV..................... Equation 2
Where Q = amount of charge lost
Make Q the subject of the equation
Q = 2E/V................. Equation 3
Give: E = 18.9 J, V = 6.0 V
Q = 2(18.9)/6
Q = 6.3 C.
Tripling the wavelength of the radiation from a monochromatic source will change the energy content of the individually radiated photons by what factor
Answer: By a factor of 1/3.
Explanation:
For a photon with wavelength λ, the energy is written as:
E = h*c/λ
where:
h is the Planck's constant:
h = 6.63*10^(-34) Js
c is the speed of light:
c = 3*10^8 m/s
Now, if we triple the wavelength of this photon, then the energy will be:
E' = (h*c)/(3*λ)
We rewrite this as:
E' = (1/3)*(h*c/λ)
And (h*c/λ) was the previous energy:
(h*c/λ) = E
Then we can replace that in the above equation to get:
E' = (1/3)*(h*c/λ) = (1/3)*E
Then if we triple the wavelength, it will change the energy content of the individually radiated photons by a factor of 1/3.
At a sports car rally, a car starting from rest accelerates uniformly at a rate of 5 m/s/s over a straight-line distance of 291 m. How long (in seconds) did it take the car to travel the 291 m
Answer:
10.8 s
Explanation:
From the question given above, the following data were obtained:
Initial velocity (u) = 0 m/s
Acceleration (a) = 5 m/s/s
Distance travelled (s) = 291 m
Time (t) taken =?
We can calculate the time taken for the car to cover the distance as follow:
s = ut + ½at²
291 = 0 × t + ½ × 5 × t²
291 = 0 + 2.5 × t²
291 = 2.5 × t²
Divide both side by 2.5
t² = 291 / 2.5
t² = 116.4
Take the square root of both side
t = √116.4
t = 10.8 s
Thus, it will take the car 10.8 s to cover the distance.
The time taken by the car to travel 291 m is calculated using the kinematics equation and it is obtained to be 10.8 seconds.
Motion in a Straight LineHere, it is given that;
The acceleration of the car is,
[tex]a = 5\,m/s^2[/tex]
The distance covered by the car is,
[tex]s = 291\,m[/tex]
Also, the car starts from rest, that means;
[tex]u = 0\,m/s[/tex]
We can use the second kinematics equation to find the time taken by the car to travel the given distance.
[tex]s = ut + \frac{1}{2}\,at^2\\291\,m = (0\,m/s \times t)+ \frac{1}{2} (5\,m/s^2\times t^2)\\\\\\291\,m = (2.5\,m/s^2\times t^2)[/tex]
implies
[tex]t = \sqrt{\frac{291\,m}{2.5\,m/s^2}}=10.78\,s\approx10.8\,s[/tex]
Learn more about 'motion in a straight line' here: https://brainly.com/question/19558242
The energy of an electromagnetic wave changes proportionally to which other
property?
A. Frequency
B.Speed
C.Shift
D.Wavelength
I know it’s not wavelength
Answer: A. frequency
Explanation:
If it’s not wavelength then it has to be frequency
If an object is thrown downward at 4.73 m/s and it falls for 6.21 seconds before landing, how fast is it falling the instant before it lands?
Answer:
65.59 m /s
Explanation:
Initial velocity u = 4.73 m/s
Final velocity v = ?
time t = 6.21 s
acceleration = g = 9.8 m /s
v = u + gt
= 4.73 + 9.8 x 6.21
= 65.59 m /s .
Coulomb's Law: Coulomb's law is F = k (q1xq2)/ r^2 where k = 9 x 10^9 C^2/m^2. a) Sketch the charges and use Coulomb's law to determine the electric force between two charged particles where q1 = -5 x 10^-3 C and q2 = -1 x 10^-3 C. Q1 and Q2 are separated by a distance of 0.25 m. b) Determine whether the electric force attractive or repulsive and explain your answer?
Answer:
a) F = 7.20 10⁵ N, b) the force between charges is repulsive.
Explanation:
For this exercise we calculate the electric forces given by Coulomb's law
[tex]F = k \frac{q_{1} q_{2} }{r^{2} }[/tex]
where in this case they indicate that q1 = 5 103 C and q2 = 1 103 C and the distance between them r = 0.25 m
let's calculate
F = [tex]9 10^{9} \ \frac{5 \ 10^{-3} \ \ 1 \ 10^{-3} }{0.25^{2} }[/tex]
F = 7.20 10⁵ N
b) when electric charges have the same sign they repel and when they have the opposite sign they attract.
In this case, charge 1 is negative and charge 2 is negative, therefore, since they both have the same sign, the force between charges is repulsive.
A pair of in-phase stereo speakers is placed side by side, 1.26 m apart. You stand directly in front of one of the speakers, 2.79 m from the speaker. What is the lowest frequency that will produce destructive interference at your location? Group of answer choices
Answer:
1264 Hz
Explanation:
We are given;
Your distance to the front of first speaker: L1 = 2.79 m
Distance between speakers; d = 1.26m
Now, your distance to second speaker can be calculated using pythagoras theorem.
Thus;
L2 = √(1.26² + 2.79²)
L2 = 3.0613 m
Let's find the wavelength from the formula;
(L1 - L2) = nλ
Where n is the order and could be; n = 0,1,2,3...
Making λ which is the wavelength the subject, we have;
(L1 - L2)/n = λ
The least frequency will occur at the wavelength when n = 1.
λ = (2.79 - 3.0613)/1
λ = -0.2713 m
We will take the absolute value and thus;
λ = 0.2713 m
Frequency is gotten from;
f = v/λ
Where v is speed of sound = 343 m/s
Thus;
f = 343/0.2713
f ≈ 1264 Hz
9. Henry ties a rope to the handle of a door. He moves the rope up and down to make wavesi He begins moving it quicker and the wave almost seems to stand still. He has made a standing wave. The areas on the wave where the amplitude is zero are called and the areas on the wave where the amplitude is the greatest are known as
Answer:
nodes; antinodes
Explanation:
For standing waves, the areas where the amplitude is zero are referred to as nodes while the areas where the amplitude is at the maximum are known as antinodes.
A standing wave derives its feature primarily from the fact that there are certain points along the medium of transmission that are apparently seeing to be standing still with no displacement whatsoever. At the same time, there exist opposing points to the points of zero displacements. These points have a maximum displacement in both the positive and negative directions. While the former is referred to as nodal points, the latter is known as the antinodal points.
