Answer:
static friction is developed between 2 surfaces in state of rest so i think answer is c.Even though the wheel is in motion, the patch of the tire in contact with the ground is stationary relative to the ground, so it is static rather than kinetic friction.
The static friction is the hindrance to an object which is trying to move from stationary state. Among the given options, the example for static friction is pushing the box that is at rest.
What is static friction?The friction that occurs when people attempt to move a stationary object on a surface without actually causing any relative motion between the body and the surface.
The static frictional force is self-regulating, which means that it will always be equivalent to and opposite to the force applied. Static friction is zero for an object at rest on a flat table.
Static friction creates an equal and opposite force that keeps the book at rest when you push horizontally with a small force.The static friction force increases to match the force as you push harder.
The maximum static friction force is eventually exceeded, and the book moves. Therefore, option B is correct.
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A construction worker drops a brick off a high scaffold. If the brick lands 5.0 s later, how fast was the brick travelling the instant before hitting the ground?
Answer:
The brick was traveling at 49 m/s the instant before hitting the ground.
Explanation:
When an object is dropped from rest in a free-falling motion, it falls with a constant acceleration called the acceleration of gravity, which value is [tex]g = 9.8 m/s^2[/tex].
The final velocity of a free-falling object after a time t is given by:
[tex]vf=g.t[/tex]
The distance traveled by a dropped object is:
[tex]\displaystyle y=\frac{gt^2}{2}[/tex]
The brick takes 5 seconds to land from the high scaffold. The speed at which it lands is:
[tex]vf=9.8\cdot 5[/tex]
vf=49 m/s
The brick was traveling at 49 m/s the instant before hitting the ground.
can someone please write this analysis of the force magnitudes calculated in problems 1 and 2 for me?
Answer:
Explanation:
i didnt got what you had said about qn 1 and 2
qn 10 :pic given
qn 11;F = m * a
The apple's acceleration is not influenced by the acceleration due to gravity for this question. In real life it most certainly is influenced by gravity.
F = m * a
F = 10 Newtons.
a = 6 m/s^2
m = 10/6 = 1.66 kg.
To win the game, a place kicker must kick a football from a point 21 m (22.9656 yd) from the goal, and the ball must clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a speed of 16 m/s at an angle of 55.3◦ from the horizontal. The acceleration of gravity is 9.8 m/s^2 By how much vertical distance does the ball clear the crossbar? Answer in units of m
In projectile horizontal distance is given by :
[tex]h = \dfrac{u^2sin^ 2\theta}{2g}[/tex]
Putting all given values, we get :
[tex]h = \dfrac{u^2sin^ 2\theta}{2g}\\\\h=\dfrac{16^2\times sin^2 \ 55.3^o}{2\times 9.8}\\\\h=13.1\ m[/tex]
Therefore, maximum height of football is 13.1 m.
Hence, this is the required solution.
Plzzzzzzzz helppp me 10 pointsssssssssssssss!!
Question:
How is the shell of a hard-boiled egg similar to the Earth’s crust?
Question:
Besides an egg, provide your own example of some object you may know that could be seen as a model of the Earth’s crust.
PLZZ help and answer BOTH
I need some help, anything will help, I just need a better understanding of this
Answer:
12 meters
Explanation:
to find this we look at the 8 on the horizontal line this is 8 seconds, you then look upwards to see the height at that point in time
Ruby wants to find out what variables affect the rate at which sugar dissolves in water. She records different information about four containers of water and sugar, as shown in the table below.
Which two containers should Ruby choose to investigate the effect that temperature has on the rate at which sugar dissolves?
Answer:
The correct answer is - containers 1 and 3.
Explanation:
In any experiment or investigation, there must be all the factors should be constant other than the variable that is changed to see the effect on the result or desired character.
In this experiment to check the effect of the temperature, there must be the only temperature is a variable that should be manipulated rest should remain constant. In container 1st and 3rd, all the variable amount of sugar, the method of mixing all are the same except temperature.
Thus, the correct answer is - 1 and 3rd.
Question 7 of 10
Which event is an example of melting?
A. People see their breath on a cold winter day.
B. Dew forms on the leaves of a tree.
C. Frost forms on a blade of grass.
O D. An ice cube forms a small puddle on the counter.
PART II – CHOOSING THE APPROPRIATE UNIT For each example below choose the appropriate unit to measure each (mm, cm, m or km). 1. Width of physics book _____ 2. Distance from New York to Utah _____ 3. Length of fingernail _____ 4. Length of hallway _____ 5. Height of a mountain _____ 6. Length of a fork _____ 7. Distance between cities _____ 8. Width of your eyeball _____
Answer:
Explanation:
In this unit of measurement for distance or length, the units are arranged from the least to the largest unit i.e
mm < cm < m < km
Where mm is millimeter, cm is centimeter, m is meter and km is kilometer.
Hence, the appropriate unit to be used depends on how small or wide the length/distance being referred to is. For instance, the length of a stapler pin should be measured in millimeter while the length of a pen should be measured in centimeter. The appropriate measurement can be determined by determining the closest unit the value falls into. For instance, there is no need to refer to a length as 1000 cm when it can be referred to as 10 m (since 100 cm equals 1 m)
1. Width of a physics book should be measured in centimeters (this is similar to length of a pen).
2. Distance from New York to Utah should be measured in kilometers (Distance between far cities or states are measured in kilometers).
3. Length of a fingernail should be measured in millimeters (this is similar to the length of a stapler pin)
4. Length of hallway should be measured in meters (This is generally larger than centimeter but lesser than kilometer)
5. Height of a mountain should be measured in kilometers (This is usually a very long distance from the earth surface)
6. Length of a fork should be measured in centimeters (This is similar to the length of a pen).
7. Distance between cities should be measured in meters (except the distance is far apart, distance between close cities are measured in meters)
8. Width of the eyeball should be measured in millimeters (similar to the length of a stapler pin and fingernail).
How far will you travel if you run for 30 seconds at 6m/sec?
A piece of wood is measured to have 2 cm x 5 cm x 3 cm of volume. Its mass is 20.0 g. What is its density?
Answer:
[tex]\boxed {\tt \frac{2}{3} \ or \ 0.666666667 \ g/cm^3}[/tex]
Explanation:
Density can be found by dividing the mass by the volume.
[tex]d=\frac{m}{v}[/tex]
The mass is 20 grams.
We have to find the volume.
To find the volume, multiply the length by the width by the height. V= l*w*h l= 2 cm, w= 5 cm, h= 3 cmV= 2 cm * 5 cm * 3 cm = 30 cm³[tex]m= 20 \ g\\v= 30 \ cm^3[/tex]
Substitute the values into the formula.
[tex]d=\frac{20 \ g}{30 \ cm^3}[/tex]
Divide.
[tex]d=\frac{2}{3} \ g/cm^3[/tex]
[tex]d= 0.666666667 \ g/cm^3[/tex]
The density is 2/3 grams per cubic centimeter.
What happens to a circuit's R, V, and I when you change the length of the wire
in the circuit?
The resistance in a circuit is directly proportional to the length of the wire. Thus as the length increases, R increases and current I decrease. But the voltage v remains constant.
What is Ohm's law ?Ohm's law states that, the voltage across a circuit is the product of the current and resistance.
Thus, V = I R
The resistance R is expressed by the expression:
R = ρ l/a
where ρ is the proportionality constant called resistivity and l and a be the length and area of the wire.
Thus, as the length increases, resistance also increases.
The increase in resistance result in a decrease the current through the circuit. Therefore, voltage remains constant. Hence, option B is correct.
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A girl tries to jump over a 0.825 m
wide creek by jumping at 3.87 m/s
at a 18.8° angle. What is her
height when she reaches the
other side of the creek?
A speed-time graph is shown below:
Speed vs. Time
What is the average acceleration of the object represented in the graph above over the eight seconds?
A) 0.5 cm/s2
B) 1.0 cm/s2
C) 1.5 cm/s2
D) 2.0 cm/s2
Answer:
The average acceleration of the object is 0.5 cm/s^2. Answer: A)
Explanation:
Average Acceleration
The average acceleration of a moving object is the rate at which the speed changed over time in a specific period. It can be calculated as follows:
[tex]\displaystyle \bar a=\frac{v_f-v_o}{t}[/tex]
Where vf is the final speed, vo is the initial speed and t is the time.
The speed-time shows the speed starts at 0 cm/s and ends at 4 cm/s over the 8 seconds period. The average acceleration is:
[tex]\displaystyle \bar a=\frac{4-0}{8}=0.5[/tex]
The average acceleration is 0.5 cm/s^2
A) Correct. The average acceleration is 0.5 cm/s^2
B) Incorrect. The average acceleration is 0.5 cm/s^2
C) Incorrect. The average acceleration is 0.5 cm/s^2
D) Incorrect. The average acceleration is 0.5 cm/s^2
Answer:
A) 0.5 cm/s2
Explanation
I took the quiz the correct answer is A
Which property of air makes it effective in protecting firefighters?
The property of air which makes it effective in protecting firefighters is that it is a poor thermal conductor.
What is air?We define air as a mixture of gasses. We know that there a re several gases that are known to compose air and among these are oxygen, carbon dioxide, noble gasses and nitrogen.
We know that air is a poor conductor of heat. As such, air does not heat up quite easily and this would help to protect the fireman from getting burnt since air does not easily allow heat to pass through it as it were, this is why the firefighters depend on the insulative property of air.
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What would be 1/2 times 800?
Answer:
The answer is 400
Explanation:
When momentum is transferred from one object to another, their combined momentum remains the same. * True or False
Answer:
true
Explanation:
hope this helps
what is kinetice energy
Answer:
energy which a body possesses by virtue of being in motion.
Answer:
kinetic energy, simply, is movement energy. it is energy which an object posses for its motion. in order to accelerate the object force must be applied. examples include:
moving your hand a ball rolling runningAt a circus, a human cannonball is shot from a cannon at 15m/s at an angle of 40° above horizontal. She
leaves the cannon 2m off the ground and lands in a net 1m off the ground. What height does she reach?
How much ground distance does she cover?
Answer:
a
The height is [tex]H = 6.74 \ m [/tex]
b
The horizontal distance is [tex]D = 23.74 \ m [/tex]
Explanation:
From the question we are told that
The speed is [tex]v = 15 \ m/s[/tex]
The angle is [tex]\theta = 40^o[/tex]
The height of the cannon from the ground is h = 2 m
The distance of the net from the ground is k = 1 m
Generally the maximum height she reaches is mathematically represented as
[tex]H = \frac{v^2 sin^2 \theta }{2 * g } + h[/tex]
=> [tex]H = \frac{(15)^2 [sin (40)]^2 }{2 * 9.8} + 2[/tex]
=> [tex]H = 6.74 \ m [/tex]
Generally from kinematic equation
[tex]s = ut + \frac{1}{2} at^2[/tex]
Here s is the displacement which is mathematically represented as
s = [-(h-k)]
=> s = -(2-1)
=> s = -1 m
There reason why s = -1 m is because upward motion canceled the downward motion remaining only the distance of the net from the ground which was covered during the first half but not covered during the second half
a = -g = -9.8
[tex]u = v sin (\theta)[/tex]
So
[tex]-1 = (vsin 40 )t + \frac{1}{2} * (-9.8) t^2[/tex]
=> [tex]-4.9t^2 + 9.6418t + 1 = 0[/tex]
using quadratic formula to solve the equation we have
[tex]t = 2.07 \ s[/tex]
Generally distance covered along the horizontal is
[tex]D = v cos (40) * 2.07[/tex]
=> [tex]D = 15 cos (40) * 2.07[/tex]
=> [tex]D = 23.74 \ m [/tex]
2. A girl throws a marshmallow that lands in her friend's mouth 2 m away. The girl threw the marshmalow
at an angle of 30 degrees. How hard did she throw the marshmallow?
Answer:
The speed at which she threw the marshmallow is approximately 4.76 m/s
Explanation:
The given in formation are;
The range in which the marshmallow was thrown = 2 m (The location of her friend)
The angle at which the marshmallow was thrown = 30 degrees
The horizontal range is given by the following formula;
[tex]R = \dfrac{u^2 \times sin(2\cdot \theta)}{g}[/tex]
Where;
R = The range = 3 m
u = The initial velocity
θ = The angle at which the marshmallow was thrown = 30°
g = The acceleration due to gravity = 9.81 m/s²
By substitution, we have;
[tex]2 = \dfrac{u^2 \times sin(2\times 30)}{9.81} = \dfrac{u^2 \times sin(60)}{9.81}[/tex]
[tex]\therefore u^2 = \dfrac{ 2 \times 9.81}{sin(60)} = \dfrac{u^2 \times sin(60)}{9.81} \approx 22.66[/tex]
u ≈ √(22.66) ≈ 4.76 m/s
u ≈ 4.76 m/s
The speed at which she threw the marshmallow ≈ 4.76 m/s.
Answer:
4.76 m/s
Explanation:
Which of the following correctly lists the energy conversions that happen when you plug a fan into an electrical outlet and turn it on?
A: chemical, nuclear, potential
B: sound,thermal, kinetic
C:sound,nuclear,electrical
D:chemical,sound,fission
A person walks 2.00 m east, then turns and goes 4.00 m west, then turns and goes back 1.00m East
what is the persons displacement?
Answer: what is the person’s distance
electric bulb connected to a 220 volt supply line draw a current of 0.05 ampere calculate the amount of coulomb super second following to the bulb
You don't need to calculate anything.
You said "0.05 Ampere".
"Ampere" means "coulomb per second".
PLS HELP ASAP!! How many calories are required to melt a 10g ice cube which is at 0° C?
A. 10 cal
B. 800 cal
C. 80 cal
D. 540 cal
Answer:
800 calories are required to melt a 10g ice cube which is at 0 degrees C.
Explanation:
hope this helps, have an amazing day
what’s the relationship between height and potential energy?
Answer:
the higher up an object is, the more potential energy it has
Explanation:
Find the direction of the sum of
these two vectors:
12.0 m
45.0°
9.66 m. A
m A,
Answer:
82.2
Explanation:
1. Surface temperatures on the planet Mars range from –89 °C to –31 °C. Express this temperature range in Kelvin.
2. The average surface temperature on Jupiter is about 165K. Express this temperature in degrees Celsius.
3. The average surface temperature on Saturn is 134K. Express this temperature in degrees Celsius.
4. The average surface temperature on the dwarf planet Pluto is 50K. Express this temperature in degrees Celsius.
5. The Sun has several regions. The apparent surface that we can see from a distance is called the photosphere. Temperatures of the photosphere range from 5,000 °C to 8,000 °C. Express this temperature range in Kelvin.
Why do we use scatter plots for most data in Physical Science? Question 1 options: because the teacher said to use scatter plots because scatter plots show 100% of the data like a pie because scatter plots show the relationship between the independent and dependent variables because scatter plots show data for categories that do not overlap
Answer:
scatter plots show the relationship between the independent and dependent variables
Explanation:
A scatter plot is a graph which shows two variables plotted along two axes (usually the x and y axes). Scatter plots are useful in establishing any form of correlation between the dependent and independent variables in any study.
Correlation simply means the degree of relationship between variables, that is, how much does one variable affect the other? When scatter plots are almost a straight line graph, there is a high correlation between the variables. When the points in a scatter plot are isolated, there is little (sometimes zero) correlation between the variables.
what is the formula for calculating gravitational potential energy
Answer:
PEgrav = m *• g • h
Explanation:
In the above equation, m represents the mass of the object, h represents the height of the object and g represents the gravitational field strength (9.8 N/kg on Earth) - sometimes referred to as the acceleration of gravity.
Hope this helps
HURRY PLEASEE
Whenever an object exerts a force on another object, the second object exerts a force of the same magnitude, but in the_______
of the first object
direction to that of the first object
A) opposite
B) same
C) right angle
D) vertical
Answer:
A)Opposite direction
Explanation:
hope this helps ;)
An airplane traveled 300 km northeast in 2.5 hours. Find the velocity of the plane.
Answer: 120 km per hour.
Explanation: 300/2.5 = 120.
