All AP Physics 1 Resources
Example Questions
Example Question #81 : Linear Motion And Momentum
The tallest Pine tree in a nearby forest is 150 meters tall. If a pine cone situated at the very top of the tree fell, how long would it take to hit the ground?
6.2 seconds
4.0 seconds
12 seconds
15 seconds
5.5 seconds
5.5 seconds
Since the pine cone starts from rest and we are given a distance we will use:
.
Solving for t:
*Note that the distance is negative since the object is falling and gravitational acceleration is downward. One could also just ignore the signs since time cannot be negative.
Example Question #82 : Linear Motion And Momentum
The bottom of a mine shaft is filled with water to a depth of 5 feet. If a rock is dropped from the surface and is heard hitting the water 5 seconds later, how deep is the mine shaft? Use and consider the travel time of the sound waves negligible.
135 meters
130 meters
125 meters
100 meters
150 meters
130 meters
Since the stone is dropped from rest and we are searching for a distance, we can use the kinematic equation :.
We can eliminate the second term, initial velocity times time because the stone is dropped.
But since the mine shaft is filled with 5 meters of water its actual depth would 130 meters.
Example Question #86 : Motion In One Dimension
A high powered cannon projectile leaves the barrel with a muzzle velocity of . If the barrel is 1.2 meters long, what is the acceleration of the bullet in the barrel? Assume uniform acceleration.
None of these
The projectile started from rest and we are given its initial velocity, the muzzle velocity that is. Use the kinematic equation: .
The initial velocity is canceled out:
Solve for a:
Example Question #363 : Ap Physics 1
Some grasshoppers can jump up to 1.7 meters in the air. What is this insects take off speed from the ground?
None of these
Use the kinematic equation . Note that the grasshoppers final speed will be equal to 0.
Square rooting both sides:
Example Question #83 : Linear Motion And Momentum
If a person drops his keys on earth from 1.6 meters and an astronaut dropped hers on the moon, which set of keys would hit the ground first? Assume air friction is negligible on Earth and that both sets of sets of keys are the same mass.
The keys will hit the ground at the same time on both Earth and the Moon.
The Moon because the pull of gravity is weaker.
The Moon because the pull of gravity is stronger.
The Earth because the pull of gravity is stronger.
The Earth because the pull of gravity is weaker.
The Earth because the pull of gravity is stronger.
The Earth's gravitational acceleration is approximately while the acceleration of gravity on the Moon is about 1.6. In other words the Earth's pull is much stronger than the Moon's. Objects will fall faster here on Earth.
Example Question #84 : Linear Motion And Momentum
For a stone thrown straight up and caught at the same height it was thrown, which of the following are true. Ignore air friction.
Acceleration of the stone is zero after being caught.
Two of these
Acceleration and velocity of the stone always point in the same direction.
Acceleration of the stone is zero at the apex when the stone pauses for a split second.
The time going up equals the time going down.
The time going up equals the time going down.
Gravity is the same at all heights with minor exceptions over great distances such as deep in the Earth and at 30,000 feet; gravity would be stronger that much closer to Earth.
Acceleration of gravity pulls everything downward- all the time and even if an object isn't moving. So acceleration and velocity can't always point in the same direction as the stones initial velocity points up.
The time traveling up will be equal to time falling as the motions just cancel each other. Gravity is slowing the stone as it travels upward until it stops very, very briefly and begins to accelerate and travel downward.
Example Question #321 : Newtonian Mechanics
A drone must accelerate down a runway at for 20 seconds until it takes off. What is the minimum length of its runway?
None of these
240 meters
420 meters
402 meters
204 meters
240 meters
Since the drone starts from rest we use and cross out the first term after the equals sign: initial velocity multiplied by time.
*Notice how the time units cancel
Example Question #322 : Newtonian Mechanics
An astronaut drops his keys while on the moon from a height of 1.6 meters. How long will it take for them to hit the ground?
2.1 seconds
1.2 seconds
0.57 seconds
1.4 seconds
2.3 seconds
1.4 seconds
We are given a distance and since the object is dropped we can cross out initial velocity in the kinematic equation: . Remember to use the acceleration for gravity on the moon. It is .
Dividing and square rooting the quotient:
Example Question #1 : Motion In Two Dimensions
An object is shot from the ground at 75m/s at an angle of 45⁰ above the horizontal. How high does the object get before beginning its descent?
420m
280m
70m
140m
140m
The velocity must be broken down into x (horizontal) and y (vertical) components. We can use the y component to find how high the object gets. To find vertical velocity, vy, use .
Next we find how long it takes to reach the top of its trajectory using .
t = 5.3s
Finally, find how high the object goes with .
Example Question #1 : Motion In Two Dimensions
An object is shot from the ground at 125m/s at an angle of 30o above the horizontal. How far away does the object land?
1350m
675m
250m
62.5m
1350m
First, find the horizontal (x) and vertical (y) components of the velocity
Next, find how long the object is in the air by calculating the time it takes it to reach the top of its path, and doubling that number.
t = 6.25s
Total time in the air is therefore 12.5s (twice this value).
Finally, find distance traveled my multiplying horizontal velocity and time.
Certified Tutor