AP Physics Final
Maximum height of athlete swinging on rope- What is the maximum height to which the 100 kg athlete swings
1.8m
In which of the following situations is the kinetic energy of the object decreasing?
A baseball is heading upward after being thrown at an angle
In which of the following situations is the object's kinetic energy decreasing?
A baseball is heading upward after being thrown at an angle
A rock of mass m is thrown horizontally off a building from a height h, as shown above. The speed of the rock as it leaves the thrower's hand at the edge of the building is vo. What is the kinetic energy of the rock just before it hits the ground?
D. 1/2mv0^2 + mgh
In Experiment 1, what is the speed of the ball the instant it makes contact with the ground?
D. 5.4 m/s
Which of the following conclusions can the student draw from the graphs, and why?
D. Since the balls have the same vertical position at any given time, they reach the ground at the same time
An astronaut stands on the surface of an asteroid. The astronaut then jumps such that the astronaut is no longer in contact with the surface. The astronaut falls back down to the surface after a short time interval. Which of the following forces CANNOT be neglected when analyzing the motion of the astronaut?
D. The gravitational force between the astronaut and the asteroid
Two identical books are stacked on a table. A third identical bok is then placed on top of the first two, causing an increase in the normal force exerted by the bottom book on the middle book, Which of the following is a correct explanation for the increase in this normal force?
D. The third book produces an additional downward force on the middle book, thus increasing the upward force exerted by the bottom book to maintain equilibrium
An object has a weight W when it is on the surface of a planet of radius R. What will be the gravitational force on the object after it has been moved to a distance of 4R from the center of the planet?
E. 1/16 W (4^2)
Balls 1 and 2 are each thrown horizontally from the same height above level ground, but ball 2 has a greater initial velocity after leaving the thrower's hand. If air resistance is negligible, how do the accelerations of the balls and the times it takes them to hit the ground compare?
E. Acceleration a- Equal Time to Hit Ground- Equal
A ball is thrown straight up in the air. When the ball reaches its highest point, which of the following is true?
E. None of the above
A steel ball supported by a stick rotates in a circle of radius r, as shown above. The direction of the net force acting on the ball when it is in the position shown is an indication by which of the following?
E. ball pointing towards the center of the circle
An object is thrown with an initial speed v near the surface of Earth. Assume that air resistance is negligible and the gravitational field is constant. If the object is thrown vertically upward, the direction and magnitude of its acceleration while it is in the air is
E. downward and constant
An object is thrown with an initial speed v near the surface of the Earth. Assume that air resistance is negligible and the gravitational field is constant. If the object is thrown horizontally, the direction and magnitude of its acceleration, while it is in the air, is
E. downward and constant
A rock of mass m is thrown horizontally off a building from a height h, as shown above. The speed of the rock as it leaves the thrower's hand at the edge of the building is vo. How much time does it take the rock to travel from the edge of the building to the ground?
E. sqrt(2h/g)
An object is sliding to the right along a straight line on a horizontal surface. The graph shows the object's velocity as a function of time. What is the object's displacement during the time depicted in the graph?
A. 0 m
K and U of object-Earth system- The student collects the data necessary to graph the object's kinetic energy as a function of time, as shown. Which of the following graphs represents the sum of the kinetic energy K and gravitational potential energy Ug of the object-Earth system as a function of time
A. straight horizontal line
While traveling in its elliptical orbit around the Sun, Mars gains speed during the part of the orbit where it is getting closer to the Sun. Which of the following can be used to explain this gain in speed?
As Mars gets closer to the Sun, the Mars-Sun system loses potential energy an Mars gains kinetic energy
The graph above shows velocity v as a function of time t for a 0.50 kg object traveling along a straight line. The graph has three segments labeled 1, 2, and 3. A rope exerts a constant force of magnitude FT on the object along its direction of motion the whole time. During segment 2 only, a frictional force of magnitude Ff is also exerted on the object. Which of the following correctly ranks the displacement ∆x for the three segments of the object's motion?
B. X3 greater than X2 greater than X1 greater than 0
Mechanical Energy of System Moving Up Ramp- For the system that only includes the object, which of the following claims best describes what happens to the mechanical energy of the system while the object is moving from the bottom of the ramp to the top of the ramp?
C. The mechanical energy of the object is constant because the kinetic energy of the object is constant
A rock of mass m is thrown horizontally off a building from a height h, as shown above. The speed of the rock as it leaves the thrower's hand at the edge of the building is vo. What is the rock's kinetic energy just before it hits the ground?
D. 1/2mv0^2 + mgh
The figure above shows the forces exerted on a block that is sliding on a horizontal surface: the gravitational force of 40 N, the 40 N normal force exerted by the surface, and a frictional force exerted to the left. The coefficient of friction between the block and the surface is 0.20. The acceleration of the block is most nearly
D. 2.0 m/s^2 to the left
Object X and object Y are at rest on a horizontal surface. Object X is in contact with object Y. The force diagrams for both objects are shown above. Which two forces make up an action-reaction pair?
D. F3 and F6, because both forces are exerted on different objects, have the same magnitude, and are in opposite directions.
The toy car shown in the figure above enters the vertical loop with an initial velocity and moves completely around the loop without friction. If the car has no means of self-propulsion, which of the following is true of the car's acceleration at the instant it is at point P?
D. It has components both downward and toward the center of the circle
A block is pulled along a surface of negligible friction by a spring scale that exerts a force F on the block. The mass of the block is 4kg, and the spring scale reads 10 N. Which of the following free-body diagrams can be used to show the magnitude and direction of all the forces exerted on the block as it is pulled along the surface?
Normal force and Gravity are equal, opposite, and large. Spring force is very small and to the right.
How does the change in KE compare- A crate is along a frictionless surface...While F is kept constant, the angle theta is now doubled but is still less than 90 degrees. Assume the crate remains in contact with the surface. As the crate slides a distance d, how does the new gain in kinetic energy compare to the change in K
The new gain is less than the change in K
A box is given a sudden push up a ramp. Friction between the box and the ramp is not negligible. Which of the following diagrams best represents the directions of the actual forces acting on the box as it moves upward after the push?
A. Arrow parallel to ramp downward (friction), arrow perpendicular to ramp (normal force), arrow straight down (gravitational force)
An object slides across a horizontal surface such that it slows down due to the force of friction that is exerted on the object. The object and the direction of its displacement are shown in the figure. Which of the following free-body diagrams could represent the forces that are exerted on the object?
A. Friction pointing to the left, shortest arrow, normal force point up equivalent to gravitation force which is pointing downward
A lion is running at constant speed toward a gazelle that is standing still, as shown in the top figure above. After several seconds, the gazelle notices the lion and accelerates directly toward him, hoping to pass the lion and force him to reverse direction. As the gazelle accelerates toward and past the lion, the lion changes direction and accelerates in pursuit of the gazelle. The lion and the gazelle eventually each reach constant but different speeds. Which of the following sets of graphs shows a reasonable representation of the velocities of the lion and the gazelle as functions of time?
A. Lion's graph starts below the x-axis, then crosses it, and then continues constantly at the top. Gazelle's graph starts at the x-axis goes straight, and then increases
A rocket is continuously firing its engines as it accelerates away from Earth
A. Rocket Kinetic Energy- Increasing, System Gravitational Potential Energy- Increasing, System Mechanical Energy- Increasing
Planet 1 orbits Star 1 and Planet 2 orbits Star 2 in circular orbits of the same radius. However, the orbital period of Planet 1 is longer than the orbital period of Planet 2. What could explain this?
A. Star 1 has less mass than Star 2
A student wants to approximate the amount of work that the force due to gravity does on the student as the student walks up a set of stairs. Which of the following measurements must the student collect in order to approximate the amount of work done by Earth on the students? Select two.
A. The mass of the student. D. The final vertical height above the initial vertical position.
An object attached to one end of a string moves in a circle at a constant speed. Which of the following is correct?
A. The object is accelerating as it moves
A ball is tossed straight up and later returns to the point from which it was launched. If the ball is subject to air resistance as well as gravity, which of the following statements is correct?
A. The speed at which the ball returns to the point of the launch si less than its speed when it was initially launched
Block curved ramp- Consider the block-Earth system. IN terms of the mechanical energy of the system, which of the following claims is correct, and why?
A. The system is open, because there is a net force exerted on the block
The figure above represents the orbits of two planets of equal mass that orbit their star in the counterclockwise direction as a double-planet system. From the point of view of an observer on either planet, the planets appear to orbit each other while also orbiting the star. The dots on the orbits represent the position of the planets at time t0, and X is the position of their center of mass at that time. Which of the following arrows best represents the acceleration of the center of mass of the double-planet system when it is at point X ?
A. diagonally (steep) downward (accelerating towards the center)
Two blocks of masses 1.0 kg and 2.0 kg, respectively, are pushed by a constant applied force F across a horizontal frictionless table with constant acceleration such that the blocks remain in contact with each other, as shown above. The 1.0 kg block pushes the 2.0 kg block with a force of 2.0 N. The acceleration of the two blocks is
B. 1.0 m/s^2
A ball is attached to one end of a string such that the ball travels in a vertical circular path near the Earth's surface. The force diagram of the ball at its lowest point in the circular path is shown above. What is the net centripetal force exerted on the ball?
B. 15N (25-10)
An object begins at position x = 0 and moves one-dimensionally along the x-axis with a velocity v expressed as a function of time t according to the graph above. At what time does the object pass through x = 0 again?
B. 20s and 30s
A block is projected up a frictionless plane with an initial speed vo. The plane is inclined 30° above the horizontal. What is the approximate acceleration of the block at the instant that it reaches its highest point on the inclined plane?
B. 5m/s^2
An object is thrown with a horizontal velocity of 20 m/s from a cliff that is 125 m above level ground. If air resistance is negligible, the time that it takes the object to fall to the ground from the cliff is most nearly
B. 5s (use sqrt(2h/g))
The diagram above represents the forces exerted on a box that a child is holding. Fn represents the force applied by the child's hand, and Fg represents the weight of the box. The child begins to raise the box with increasing speed. Which of the following claims about force Fh that is exerted by the box on the child's hand as the box is being raised?
B. Fh = Fn, where Fn is larger as the box is being raised than when it was being held.
A tennis ball is thrown against a vertical concrete wall that is fixed to the ground. The ball bounces off the wall. How does the force exerted by the ball on the wall compare with the force exerted by the wall on the ball?
B. the forces exerted by the ball and the wall have the same magnitude
A student makes the necessary measurements to create the graph shown, which represents the vertical component of the velocity as a function of time for the dart and for the target from t=0t=0 until the instant the dart hits the target. At t=0t=0, the target is a vertical distance hh above the dart. The curves for the dart and the target each have the same area between them and the horizontal axis. Both curves also have the same slope. Which of the following is the best method to determine the distance hh from the graph?
B. Find twice the area under the curve for the darts data
The figures show a cart moving over the top of a hill (Case 1), moving at the bottom of a dip (Case 2), and moving at the top of a vertical loop (Case 3). In each case, the normal force acting on the car is Fn and the weight of the car is Fg. In which case is it always true that Fn﹥Fg and in which case is it always true that Fn﹤Fg?
B. Fn﹥Fg - Case 2, Fn﹤Fg- Case 1
One end of a string is attached to a vertical pole with the other end of the string attached to a ball that swings in a horizontal circular path, as shown. Which of the following free-body diagrams represents the forces exerted on the ball?
B. One arrow pointing up and to the left, and the other straight down
A ball of mass M swings in a horizontal circle at the end of a string of radius R at a constant tangential speed v0. A student gradually pulls the string inward such that the radius of the circle decreases while keeping the tangential speed v0 of the ball constant, as shown above. Which of the following graphs best represents the acceleration a of the ball as a function of time t?
B. Positive Exponential Graph
Blocks X Y and Z are hanging from identical strings. Which of the following free-body diagrams could represent the forces exerted on block Y?
B. Tension Up- upward and long, Tension down- down and short, Gravity- down and short
A kitten sits in a lightweight basket near the edge of a table. A person accidentally knocks the basket off the table. As the kitten and basket fall, the kitten rolls, turns, kicks, and catches the basket in its claws. The basket lands on the floor with the kitten safely inside. If air resistance is negligible, what is the acceleration of the kitten-basket system while the kitten and basket are in midair?
B. The acceleration is directed downward with magnitude equal to g because the system is a projectile
A planet travels in an elliptical path around a star, as shown in the figure. As the planet gets closer to the star, the gravitational force that the star exerts on the planet increases. Which statement of reasoning best supports and correctly identifies what happens to the magnitude of the force that the planet exerts on the star as the planet gets closer to the star?
B. The force increases because it is part of Newton's third law pair of forces with the force that the star exerts on planet
Which of the following must be true for the cart to remain on the track when it is at point P?
B. The net force exerted on the cart must be equal to or greater than the weight of the cart
A crate is on a horizontal frictionless surface. A force of magnitude F is exerted on the crate at an angle θ to the horizontal, as shown in the figure above, causing the crate to slide to the right. The surface exerts a normal force of magnitude FN on the crate. As the crate slides a distance d, it gains an amount of kinetic energy ∆K. While F is kept constant, the angle θ is now doubled but is still less than 90o. Assume the crate remains in contact with the surface. How does the new normal force exerted on the crate compare to FN ?
B. The new normal force is less than FN
An object's velocity v as a function of time t is given in the graph above. Which of the following statements is true about the motion of the object?
B. The object's initial and final positions are the same
A person throws a marble straight up into the air, releasing it a short height above the ground and catching it at that same height. If air resistance is negligible, which of the following graphs of position y versus time t is correct for the motion of the marble as it goes up and then comes down?
B. Upside down curve
A student drops a rock from the top of a cliff such that the rock falls downward toward Earth's surface in the absence of air resistance. The downward direction is considered to be the positive direction. The graph shows the rock's velocity as a function of time. Which of the following methods should be used to determine the total distance traveled by the rock after 4s?
B. Use the area under the curve, as its states that the rock traveled 80 meters in total
Two students want to determine the speed at which a ball is released when thrown vertically upward into the air. One student throws the ball into the air while the other student measures the total time that the ball is in the air. The students use a meterstick to measure the release height of the ball. Which of the following equations should the students use to determine the speed at which the ball was released?
B. Use y = y0 + vy0t + 1/2ayt^2 from the moment in time in which the ball was released to the moment in time in which the ball hits the ground.
Suppose that Experiment 1 and Experiment 2 are conducted at the same time; one student drops the ball from rest at the same instant that a second student horizontally rolls an identical off the table. After both balls have traveled half their vertical distance to the floor, what is the acceleration of the center of mass of the two-ball system relative to Earth?
B. equal to g
Object A is released from rest at height h. At the same instant, object B is thrown downward from the same location. Which of the following graphs of speed of v as a function of time t is correct for the two objects?
B. graph where B and A are parallel but B has a higher starting point on the y-axis
An object is sliding to the right along a straight line on a horizontal surface. The graph shows the object's velocity as a function of time. What is the object's displacement during the time depicted in the graph?
C. 0m/s
At time t=0t=0, a moving cart on a horizontal track is at position 0.5m0.5m. Using a motion detector, students generate a graph of the cart's velocity as a function of time, as shown above. At t=2.5st=2.5s, the cart's position is most nearly
C. 1.75
A ball is dropped from rest and falls to the floor. The initial gravitational potential energy of the ball-Earth-floor system is 10J. The ball then bounces back up to a height where the gravitational potential energy is 7J. What is the mechanical energy of the ball-Earth-floor system the instant the ball left the floor?
C. 7J
Assume the elevator is moving at constant speed, and consider the bottom box in the stack that has two boxes of mass 2M. Let Ffloor, be the force exerted by the floor on the box, Fg be the force exerted by gravity on the box, and Fbox be the force exerted by the top box on the bottom box. Which of the following best represents the forces exerted on the bottom box?
C. Big arrow up, two small arrows down
Blocks A and B, of masses mm and 2m2m, respectively, are connected by a light string and pulled across a surface of negligible friction with a constant force F1, as shown above. The acceleration of the blocks is aa. The force of the string pulling block B forward has magnitude F2. Which of the following claims correctly describes the relationship between the magnitude of the forces acting on the blocks?
C. F1 is greater than F2
Three blocks are pushed along a rough surface by a force with magnitude P, as shown above. FC is the magnitude of the contact force between blocks 2 and 3, and Ff, FN, and FG are the magnitudes of the friction, normal, and gravitational forces on block 3, respectively. Which of the following is a correct free-body diagram for block 3?
C. F1 is the smallest, Fn is equal to Fg and Fc is the biggest
The motion of a particle along a straight line is represented by the position versus time graph above. At which of the labeled points on the graph is the magnitude of the acceleration of the particle greatest?
C. Point C
The graphs above represent the position x, velocity v, and acceleration a, as a function of time t for a marble moving in one dimension. Which of the following could describe the motion of the marble?
C. Rolling up a ramp and then rolling back down
The system is moving and accelerating upward. A pair of scissors cuts the rope. Which of the following describes the motion of the 10 kg10 kg block immediately after the rope has been cut?
C. The block continues to move upward but begins to accelerate downward
An astronaut in the space station appears weightless because the astronaut seems to float. Which of the following claims is true about the force exerted on the astronaut by Earth?
C. The force exerted on the astronaut by Earth is equal to the force exerted on Earth by the astronaut
The graph above represents position x versus time t for an object being acted on by a constant force. The average speed during the interval between 1 s and 2 s is most nearly
D. 6m/s
Block projectile motion energy- The block leaves the track horizontally and strikes the ground at distance D from te edge of the track as shown. Which of the following statements is correct about the scenario? Select two.
C. The total mechanical energy of the system containing only the block increases from the moment of release to the moment it strikes the ground D. The total mechanical energy of the block-Earth system remains constant
Which of the following graphs could represent the vertical component of the velocity as a function of time for the dart and the target immediately after the dart is launched and the target begins to fall?
D. Dart graph goes downward in the 1st quad starting above the origin. The target graph starts at the origin and goes diagonally downward in the 4th quad.
Figure 1 shows a displacement-versus-time graph for the dart. Figure 2 shows a displacement-versus-time graph for the target. For both graphs, the component of the displacement is not indicated. Which displacement component, horizontal or vertical, is represented by the graph for each object?
D. Dart- Vertical Target- Vertical
A cart of mass m is moving with speed v on a smooth track when it encounters a vertical loop of radius R, as shown above. The cart moves along the inside of the entire loop without leaving the track. All frictional forces are negligible. Which of the following free-body diagrams shows the force or forces exerted on the cart at point Q?
D. Normal- to the right and long, Gravity- down and short
An amusement park ride has two identical carriages that revolve around the center of the ride's axle, as shown in the figure. Both carts travel at a constant tangential speed at all points along the circular path. At what position is the total mechanical energy of the cart-cart-Earth system at its maximum value?
D. The total energy of the Earth-Ferris wheel ride is constant.
A person holds a book at rest a few feet above a table. The person then lowers the book at a slow constant speed and places it on the table. Which of the following accurately describes the change in the total mechanical energy of the Earth-book system?
D. The total mechanical energy decreases because the person does negative work on the book by exerting a force on the book in the direction opposite to its displacement
A comet passes by a planet with a speed vo such that the comet travels in a straight line at the instant shown in the figure. The comet's tangential acceleration, centripetal acceleration, and force due to gravity from the planet at this location are provided in the table. Astronomers observe that the comet continues to travel in a nearly straight line, even though calculations show that the gravitational force exerted by the planet should cause the comet to move in a circular orbit. Why does the comet not travel in a circular path around the planet after the instant shown in the figure?
D. There must be another object such that the gravitational forces exerted on the comet are balanced at this location.
A cart is constrained to move along a straight line. A varying net force along the direction of motion is exerted on the cart. The cart's velocity v as a function of time t is shown in the graph above. The five labeled points divide the graph into four sections. Which of the following correctly ranks the magnitude of the average acceleration of the cart during the four sections of the graph?
D. aCD﹥aAB﹥aDE﹥aBC