Midterm Exam Review (PHYSICS)

If an object is launched in the air at a velocity of +6.0 m/s, what is its velocity when it returns to the ground?

6.0 m/s

A light is blinking at a constant rate and is attached to a moving cart. If you took a vide of the cart and light, how would the light blinks be spaced out if the cart were moving at a constant speed?

A light is blinking at a constant rate and is attached to a moving cart. If you took a video of the cart and light, how would the light blinks be spaced out if the cart were speeding up as it moves to the right?

A light is blinking at a constant rate and is attached to a moving cart. If you took a vide of the cart and light, how would the light blinks be spaced out if the cart were slowing down as it moves to the right?

On the moon, there is no air resistance. If that’s the case, which would strike the moon’s surface first if you dropped a bowling ball and a feather from the same height at the same height?

They would hit the ground at the same time

If an object has zero acceleration, what TWO things could the object be doing?

Moving at a constant rate or not moving.

A distance vs. time graph is shown. What is the motion of this object?

No velocity

A distance vs. time graph is shown. What is the motion of this object?

Constant velocity

A distance vs. time graph is shown. What is the motion of this object?

Speeding up

A speed vs time graph is shown. What is the motion of this object?

Constant velocity

A speed vs time graph is shown. What is the motion of this object?

Speeding up

Why does the horizontal speed of an object stay the same when thrown off a cliff?

Gravity acts vertically

An object is thrown horizontally off of a cliff at a speed of 70 m/s. After 5 seconds of falling, what is the horizontal speed of the object?

70 m/s

What is displacement?

A change in an object’s position

What is a person’s displacement if they walk 500 m North, then 200 m South, then 400 m North?

700 m North

What CONSTANT acceleration do objects experience when thrown in any direction in the absence of air resistance?

Downward acceleration of 9.8m/s²

What is the name for the shape of a projectile’s path if thrown at an angle through the air or launched horizontally off of a cliff?

Parabola

In the absence of air resistance, which would strike the ground first if dropped from the same height - a bullet you just let go of, or a bullet fired horizontally at a speed of 500 m/s?

They would strike the ground at the same time because horizontal and vertical motion are independent from each other

If you launch a ball at an angle above the ground, what angle will give the ball the greatest range?

45°

A car is traveling north and getting slower. What is the direction of the car’s acceleration?

South

What is meant by the term “equilibrium” as it applies to forces?

The object is in a constant state of motion because the forces acting on it are balanced

A horizontal force is applied to a box at rest. Which is greater — the force to start the box or the force to keep the box moving at a constant speed?

The force to start the box

What is newton’s third law?

For every action force, there is an equal and opposite reaction force.

What is an application of Newton’s third law?

When walking, your foot pushes backwards on the ground, and the ground pushes you forward, allowing you to move

A force of 10 N is applied to the east on a box. If you want to keep the box moving at a constant velocity, how many Newtons of force must be applied to the west on the box?

10 N

If a car is resting on a hill, which way would the normal force go?

Up

If a car is resting on a hill, which way would the weight go?

Down

If a car is resting on a hill, which way would friction go?

Up (since its at rest)

Two forces are applied to an object. How would these forces have to act to give the object the greatest acceleration?

In the same direction

Two forces are applied to an object. How would these forces have to act to give the object the least acceleration?

In opposite directions

Inertia is another name for

mass

In terms of how hard or easy it is to move an object, what does it mean if the coefficient of friction between the object and the surface is high?

The surface has a high amount of friction

In terms of how hard or easy it is to move an object, what does it mean if the coefficient of friction between the object and the surface is low?

The surface has a low amount of friction

What is potential energy based on?

Mass, gravity, and height

How could you move an object to give it more PE?

Raise it higher from the ground

How could you move an object to give it less PE?

Lower it closer to the ground

An object is at rest at the top of the hill and has 120 Joules of PE. What will its PE and KE be when the object slides to a point halfway down the hill?

They will both be 60 J, half of the original Joules at the top.

Ignoring outside forces like friction or air resistance, how does the total energy (sum of kinetic and potential energy) change as an object does something like sliding down a hill?

The PE decreases while the KE increases.

How does KE increase or decrease?

When an objects mass and speed change

A pendulum is swing back and forth. At what points along its oscillation is the potential energy the highest and lowest?

Highest at the highest point of the swing, lowest at the lowest point

A pendulum is swing back and forth. At what points along its oscillation is the kinetic energy the highest and lowest?

Highest at the lowest point of the swing, lowest at the highest point of the swing

Work is done to

change the energy of an object

In order for work to be done by a force, the force must be [_____] to an object’s displacement.

Parallel

The force on an object only does work if it

changes the objects energy

What is power?

The rate at which work is done

If an object loses PE as it falls, it must [_____] the same amount of KE that it loses.

Gain

A person climbs a ladder to a height of 6.0 m. Another person of the same mass walks up a ramp to a height of 6.0 m. Compare the potential energy of the two people

Both have the same potential energy because PE only depends on vertical height.

What does momentum depend on?

Mass and Velocity

If you provide an impulse of 50*kg m/s to an object, what is its change in momentum?

It is the same as the applied

If you double the momentum of an object, how much did the impulse need to change by?

The impulse must also double

Imagine you jump off of your desk. Whether you land on a hard floor or a squishy pad, your momentum change is the same because you went from high momentum right before landing to zero momentum right after landing. If the momentum change is the same no matter what, WHY is the force on you much less if you land on the squishy pad?

It takes longer for the change in momentum to happen

A heavy object and a light object are dropped from the same height at the same time in the absence of air resistance. Which object will hit th ground at a higher speed?

They will hit the ground at the same speed.

A heavy object and a light object are dropped from the same height at the same time in the absence of air resistance. Which object will have a higher momentum when it lands?

The heavy object, because momentum depends on mass and velocity.

In the absence of outside forces, momentum

is always conserved

For momentum, what is the trade-off between two objects that collide?

The second object with DOUBLE the mass needs to have HALF of the speed of the first object.