How much power is used if an athlete lifts a 50N weight up 2 meters in 10 seconds?

Answer: A. frequency

Explanation:

If it’s not wavelength then it has to be frequency

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

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 .

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.

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

Answer:

3.75Ns

Explanation:

Given data

F= 75N

time= 0.05seconds

We know that

P=Ft

substitute

P=75*0.05

P=3.75Ns

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.

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

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.

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.

Here, 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

Answer:

Double

Explanation:

Newton's second law of motion states that the acceleration of an object is directly proportional to and acts in the same direction as the net force acting on the object. The second law of motion can be represented by the equation:

F ∝ a;

F = ma

where m is the mass which is the constant of proportionality, F is the net force and a is the acceleration of the object.

Hence for a car with a constant mass, if the engine is replace with one that doubles the net force, the acceleration of the car would also double.

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.

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]

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!

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.

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]

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.

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

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

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)

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

Answer:

Remains the same

Explanation:

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

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

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

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

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

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.

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.