physics exam study guide
When a car's velocity is negative and its acceleration is negative, what is happening to the car's motion?
a. The car speeds up.
Which would hit the ground first if dropped from the same height in a vacuum-a feather or a metal bolt?
a. They would hit the ground at the same time. Correct
What is the path of a projectile (in the absence of friction)?
a. a parabola
You are throwing a ball for the second time. If the ball leaves your hand with twice the velocity it had on your first throw, its horizontal range R (compared to your first serve) would be
a. four times as much.
Acceleration due to gravity is also called
a. free-fall acceleration.
The graph above describes the motion of a ball. At what point is the velocity of the ball equal to its velocity at B?
a. none of the above
Roll a bowling ball off the edge of a table. As it falls, its horizontal component of velocity
a. remains constant.
A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, neglecting air drag, its horizontal component of velocity
a. remains unchanged.
The graph above describes the motion of a cyclist. During the interval shown, the cyclist is
a. speeding up.
The path of a projectile through space is called its:
a. trajectory
In the graph above, a toy car rolls from +3 m to +5 m. Which of the following statements is true?
a. xi = +3 m
The displacement x of an object moving along the x-axis is shown above as a function of time t. The acceleration of this object must be
a. zero
According to the graph above, during which interval does the cat have the greatest positive velocity?
b. 0.0-5.0 s
An object is dropped and freely falls to the ground with an acceleration of 1 g. If it is thrown upward at an angle instead, its acceleration will be
b. 1 g downward.
A ball is thrown up from street level and returns to its original height as shown in the graph below. Use the graph to find the initial velocity of the ball.
b. 30 m/s
A stone is thrown horizontally from the top of a cliff. One second after it has left your hand, its vertical distance below the top of the cliff is
b. 5 m.
A ball is thrown at an original speed of 8.0 m/s at an angle of 35° above the horizontal. What is the speed of the ball when it returns to the same horizontal level?
b. 8.0 m/s
The figure above shows the path of a ball tossed from a building. Air resistance is ignored. At what point of the ball's path shown in the figure above is the vertical component of the ball's velocity zero?
b. B
At time t = 0, Car X traveling with speed v0 passes Car Y. which is just starting to move. Both cars then travel on two parallel lanes of the same straight road. The graphs of speed v versus time t for both cars are shown above. Which of the following is true at time t = 20 seconds?
b. Car Y is behind car X.
When a football in a field goal attempt reaches its maximum height, how does its speed compare to its initial speed?
b. It is less than its initial speed.
When an object is released from rest and falls in the absence of friction, which of the following is true concerning its motion?
b. Its acceleration is constant.
A bullet is fired horizontally, and at the same instant a second bullet is dropped from the same height. Ignore air resistance. Compare the times of fall of the two bullets.
b. They hit at the same time.
Which of the following does not exhibit parabolic motion?
b. a flat piece of paper released from a window
A baseball catcher throws a ball vertically upward and catches it in the same spot as it returns to the mitt. At what point in the ball's path does it experience zero velocity and nonzero acceleration at the same time?
b. at the top of its path
A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, neglecting air drag, its vertical component of velocity
b. decreases.
Ball A is dropped from the top of a building. One second later, ball B is dropped from the same building. As time progresses, the distance between them
b. increases.
The diagram below shows the trajectories of two balls. The magnitude of the initial velocity is vi, the launch angle is q, and the horizontal and vertical components of the initial velocity are vxi and vyi.
b. is greater than the value for ball B.
A stone is thrown horizontally from the top of a tower at the same instant a ball is dropped vertically. Which object is traveling faster when it hits the level ground below?
b. the stone
If you run a complete loop around an outdoor track (400 m), in 100 s, your average velocity is
b. zero.
A ball is thrown up from street level and returns to its original height as shown in the graph below. What is the acceleration of the ball at 3s?.
c. -9.8 m/s2
A plane flying horizontally at a speed of 50.0 m/s and at an elevation of 160 m drops a package. Two seconds later it drops a second package. How far apart will the two packages land on the ground?
c. 100 m
Moustapha Jones drives east at 100km/hr for 3 hours then back west at 80km/hr for 1.5 hours. Which pair of answers gives his average speed and average velocity?
c. 93.3km/hr, 40km/hr east
A hunter on level ground fires a bullet at an angle of 2 degrees below the horizontal while simultaneously dropping another bullet from the level of the rifle. Which bullet will hit the ground first?
d. the fired one
The diagram below shows the trajectories of two balls. The magnitude of the initial velocity is vi, the launch angle is q, and the horizontal and vertical components of the initial velocity are vxi and vyi.
Compare the values of vxi. The value for ball A
Moustapha Jones reaches the bottom of a hill on his bike moving at a speed of 8.6 m/s when his chain breaks. He coasts up the hill until he comes to a stop after 3.5 s. Find his acceleration while on the hill, and the distance he travelled up the hill.
a. -2.46m/s2, 15.1m
An object is dropped and freely falls to the ground with an acceleration of 1 g. If it is thrown upward at an angle instead, its acceleration will be
a. 1 g downward.
Two projectiles are fired from ground level at equal speeds but different angles. One is fired at an angle of 30 degrees and the other at 60 degrees. The projectile to hit the ground first will be the one fired at (neglect air resistance)
a. 30 degrees
A ball is thrown vertically upward with a speed v. An identical second ball is thrown upward with a speed 2v (twice as fast). What is the ratio of the maximum height of the second ball to that of the first ball? (How many times higher does the second ball go than the first ball?)
a. 4:1
The driver of a car traveling at 110 km/h slams on the brakes so that the car undergoes a constant acceleration, skidding to a complete stop in 4.5 s. What is the average acceleration of the car during braking?
a. 6.79 m/s2
The figure above shows the path of a ball tossed from a building. Air resistance is ignored. In the figure above, the magnitude of the ball's velocity is greatest at location
a. D.
Suppose a ball is thrown straight up, reaches a maximum height, then falls to its initial height. Make a statement about the direction of the velocity and acceleration as the ball is going up.
a. Its velocity points upward and its acceleration points downward.
A soldier throws a grenade horizontally from the top of a cliff. Which of the following curves best describes the path taken by the grenade?
a. Parabola
At time t = 0, Car X traveling with speed v0 passes Car Y. which is just starting to move. Both cars then travel on two parallel lanes of the same straight road. The graphs of speed v versus time t for both cars are shown above. From time t = 0 to time t = 40 seconds, the areas under both curves are equal. Therefore, which of the following is true at time t = 40 seconds?
c. Car Y is passing car X.
When a car's velocity is positive and its acceleration is negative, what is happening to the car's motion?
c. The car slows down.
A brick is dropped from the top of a building. A second brick is thrown straight down from the same building. They are released at the same time. Neglect air resistance. Compare the accelerations of the two bricks.
c. The two bricks accelerate at the same rate.
Two objects are thrown from the top of a tall building. One is thrown up, and the other is thrown down, both with the same initial speed. What are their speeds when they hit the street?
c. They are traveling at the same speed.
Which of the following is not an example of projectile motion?
c. a hot-air balloon drifting toward Earth
A pilot drops a bomb from a plane flying horizontally at a constant speed. Neglecting air resistance, when the bomb hits the ground the horizontal location of the plane will
c. be over the bomb.
The figure above shows the path of a ball tossed from a building. Air resistance is ignored. In the figure above, the horizontal component of the ball's velocity at A is
c. equal to the horizontal component of its initial velocity.
Suppose a ball is thrown straight up. What is its acceleration just before it reaches its highest point?
c. exactly g
Suppose you are given a position versus time graph. The slope of a line drawn tangent to a point on the curve of this graph describes what quantity?
c. instantaneous velocity
The diagram below shows the trajectories of two balls. The magnitude of the initial velocity is vi, the launch angle is q, and the horizontal and vertical components of the initial velocity are vxi and vyi.
c. is greater than the value for ball B.
In the graph above, what is the correct description of any location to the left of the zero?
c. negative position
Which of the following is the motion of objects moving in two dimensions under the influence of gravity?
c. projectile motion
Ball A is dropped from the top of a building. One second later, ball B is dropped from the same building. As time progresses, the difference in their speeds
c. remains constant.
A bullet fired horizontally over level ground hits the ground in 0.5 second. If it had been fired with twice the speed in the same direction, it would have hit the ground in
d. 0.5 s.
An Olympic athlete throws a javelin at four different angles above the horizontal, each with the same speed: 30°, 40°, 60°, and 80°. Which two throws cause the javelin to land the same distance away?
d. 30° and 60°
At what angle should a water-gun be aimed in order for the water to land with the greatest horizontal range?
d. 45°
An object is released from rest on a planet that has no atmosphere. The object falls freely for 3.0 meters in the first second. What is the magnitude of the acceleration due to gravity on the planet?
d. 6.0 m/s2
The driver of a car traveling at 110 km/h slams on the brakes so that the car undergoes a constant acceleration, skidding to a complete stop in 4.5 s. If the car skids in a straight line for the entire length of the stopping distance, how long are its skid marks?
d. 7.0 x 101 m
Which of the following situations represents a negative displacement? (Assume positive position is measured vertically upward along a y-axis.)
d. A cat jumps from a tree limb to the ground.
A soccer ball is kicked into the air with an initial vertical velocity of +49 meters per second and a horizontal velocity of +19.6 meters per second. The diagram representing the vertical and horizontal velocity of the ball after 2 seconds of flight is:
d. B
A ball is thrown straight up, reaches a maximum height, then falls to its initial height. Make a statement about the direction of the velocity and acceleration as the ball is coming down.
d. Both its velocity and its acceleration point downward.
The figure above shows the path of a ball tossed from a building. Air resistance is ignored. In the figure above, at which point is the ball's speed about equal to the speed at which it was tossed?
d. C
Which of the following statements applies to the motion of a ball rising and then falling in free fall? I. The ball has constant acceleration as it moves upward. II. The ball has constant acceleration at the top of its path. III. The ball has constant acceleration as it moves downward.
d. I, II, and III
Suppose a ball is thrown straight up. Make a statement about the velocity and the acceleration when the ball reaches the highest point.
d. Its velocity is zero and its acceleration is not zero.
Two balls are thrown horizontally. Ball C is thrown with a force of 20 N, and ball D is thrown with a force of 40 N. Assuming all other factors are equal, ball D will fall toward the ground
d. at the same rate as ball C.
The diagram below shows the trajectories of two balls. The magnitude of the initial velocity is vi, the launch angle is q, and the horizontal and vertical components of the initial velocity are vxi and vyi. Compare the values of qi. The value for ball A
d. is equal to the value for ball B.
A hunter on level ground fires a bullet at an angle of 10 degrees above the horizontal while simultaneously dropping another bullet from the level of the rifle. Which bullet will hit the ground first?
d. the dropped one