ap physics 1 midterm

in object 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? a) The object is not moving from T=4 s to T=10 s b) The objects initial and final positions are the same c) The object is slowing down from t=14 s to t=16 s d) The average acceleration of the object from t=0 s to t=4s is different from the acceleration from t=34 s to t=36 s

b) The objects initial and final positions are the same

an object begins at position X=0 and moves one dimensionally along the Xaxis 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? a) between 10S and 20S b) between 20s and 30s c) at 30S exactly d) between 30S and 40S e) after 40s

b) between 20S and 30S

A block is projected up a friction this plane with an initial speed Vo. The plane is inclined 30° above the horizontal. What is the approximate acceleration of a block at the instant that it reaches its highest point on the inclined plane?

b) 5m/s² down the incline

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

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) (3 arrows: one perpendicular to the ramp pointing up, the gravity arrow going directly down, and the friction arrow facing southwest)

Blocks A and B, of masses m and 2m, 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 a. 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?

b) F1 is greater than F2.

A lion is running at constant speed towards a gazelle that is standing still, as shown in the top figure above. After several seconds, the gazelle notices the lien and accelerates directly toward him, hoping to pass the line and force him to reverse direction. As the gazelle accelerates toward in past the lien, the lien changes direction and accelerates in pursuit of the gazelle. The lion and the gazelle eventually reach Constant but different speeds. Which of the following sets of graphs shows a reasonable representation of the velocity of the line in the gazelle as functions of time?

a) (The graph for the lion starts under the timeline and goes to positive. do you graph for the gazelle we have starts constantly on the timeline and then rises in velocity)

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 book 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

A ball is thrown straight up in the air. When the ball reaches its highest point, which of the following is true? a) it is in equilibrium b) it has zero acceleration c) it has maximum momentum d) it has maximum kinetic energy e) none of the above

e) none of the above

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) √2h/g

An object attached to one end of a string moves in a circle at constant speed. Which of the following is correct?

a) The object is accelerating as it moves.

The figure above shows the position of a moon that orbits a planet in an elliptical path. Two specific locations of the moon, position A and position B, are labeled.

a) Toward the planet

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) (arrow pointing to the southwest corner)

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) (small friction arrow pointing left, longer normal and gravity force arrows)

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) 0m

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) 0m b) 1m c) 8m d) 16m

a) 0m

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 space station has a mass M and orbits Earth in a circular orbit at a height above Earth's surface. A payload of mass m, where m<M, is delivered to the space station. Soon after, the space station's orbit is adjusted so that it is 50 km farther away from Earth's surface than before. Which of the following best describes the effects of these changes on Earth's gravitational field strength at the space station's new location?

a) The increase in mass of the space station has no effect on the field strength, and the increase in orbital radius decreases the field strength.

The graph above shows velocity V as a function of time T for a 0.50kg object traveling along the 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 ꕔx for the three segments of the object's motion?

a) ꕔx3>ꕔx2>ꕔx1>0

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) (a starts in the very corner and b above it on the velocity line. they are parallel)

Three identical blocks, X, Y, and Z, hang from identical strings, as shown in the figure. Which of the following free-body diagrams could represent the forces exerted on block Y?

b) (equal sized arrows of tension down and gravity; long tension up arrow)

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) (looks like an upside down U)

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) (non linear graph with increasing acceleration)

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) (only 2 forces are the downward force of gravity and the tension exerted in the direction of the string)

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/s2

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 is correct 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 student wants to launch a toy dart toward a target that hangs from a light string. At time t=0, the dart is launched with an initial speed v0 at an angle θ0 above the horizontal ground. At the instant the dart is launched, the string is cut such that the target begins to fall straight down. The positive horizontal direction is considered to be to the right, and the positive vertical direction is considered to be up. 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=0 until the instant the dart hits the target. At t=0, the target is a vertical distance h 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 h from the graph?

b) Find twice the area under the curve for the dart's data.

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 a Newton's third law pair of forces with the force that the star exerts on the planet.

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 planet has two moons, Moon A and Moon B, that orbit at different distances from the planet's center, as shown. Astronomers collect data regarding the planet, the two moons, and their obits. The astronomers are able to estimate the planet's radius and mass. The masses of the two moons are determined to be 2M for Moon A and M for Moon B. It is observed that the distance between Moon B and the planet is two times that of the distance between Moon A and the planet. How does force exerted from the planet on Moon A compare to the force exerted from the planet on Moon B ?

b) The gravitational force exerted from the planet on Moon A is eight times larger than the gravitational force exerted from the planet on Moon B

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 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.

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+1/2ayt² from the moment in time in which the ball was released to the moment in time in which the ball hits the ground

A student wants to investigate the motion of a ball by conducting two different experiments, as shown in Figure 1 and Figure 2 above. In Experiment 1, the student releases a ball from rest and uses a slow-motion camera to film the ball as it falls to the ground. Using video analysis, the student is able to plot the ball's horizontal position x and vertical position y as a function of time t. In Experiment 2, the student horizontally rolls the same ball off a table, and uses video analysis to plot the ball's horizontal position x and vertical position y as a function of time t starting from the instant the ball leaves the table. The graphs from each experiment are shown above along with each graph's best-fit curve line. 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

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 rocks 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 it states that the rock traveled 80 meters in total

The stacks of boxes shown in the figure above are inside an elevator that is moving upward. The masses of the boxes are given in terms of the mass M of the lightest box. 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) (small Fg and Fbox arrows pointing down & long Ffloor arrow pointing up)

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 10N. 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?

c) (small Fspring arrow, long Fnormal and Fgravity arrows)

At time t=0, A moving cart on a horizontal track is at position 0.5m . Using a motion detector, students generate a graph of the carts velocity as a function of time, as shown above. at t=2.5 s, the carts position is most nearly a) 0.5m b) 1.25m c) 1.75m d) 2m

c) 1.75m

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? a) Rolling along the floor and then bouncing off a wall b) Rolling down one side of a bowl and then rolling up the other side c) Rolling up a ramp and then rolling back down d) Falling and then bouncing elastically off a hard floor

c) Rolling up a ramp and then rolling back down

Two blocks are connected by a rope, as shown above. The masses of the blocks are 5 kg for the upper block and 10 kg for the lower block. An upward applied force of magnitude F acts on the upper block. The system is moving and accelerating upward. A pair of scissors cuts the rope. Which of the following describes the motion of the 10 kg block immediately after the rope has been cut?

c) The block continues to move upward but begins to accelerate downward

A space station has a mass M and orbits Earth in a circular orbit at a height above Earth's surface. 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 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? a) a b) b c) c d) d e) e

c) c

A student wants to launch a toy dart toward a target that hangs from a light string. At time t=0, the dart is launched with an initial speed v0 at an angle θ0 above the horizontal ground. At the instant the dart is launched, the string is cut such that the target begins to fall straight down. The positive horizontal direction is considered to be to the right, and the positive vertical direction is considered to be up. 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) (darts graph starts positive and decreases as a function of time as it travels toward the target. target graph is under the x-axis &acceleration due to gravity is directed in the negative direction)

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/s2 to the left

A student wants to investigate the motion of a ball by conducting two different experiments, as shown in Figure 1 and Figure 2 above. In Experiment 1, the student releases a ball from rest and uses a slow-motion camera to film the ball as it falls to the ground. Using video analysis, the student is able to plot the ball's horizontal position x and vertical position y as a function of time t. In Experiment 2, the student horizontally rolls the same ball off a table, and uses video analysis to plot the ball's horizontal position x and vertical position y as a function of time t starting from the instant the ball leaves the table. The graphs from each experiment are shown above along with each graph's best-fit curve line. In Experiment 1, what is the speed of the ball the instant it makes contact with the ground?

d) 5.4m/s

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 1s and 2s is most nearly a) 2m/s b) 4m/s c) 5m/s d) 6m/s e) 8m/s

d) 6m/s

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 circular 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 student wants to investigate the motion of a ball by conducting two different experiments, as shown in Figure 1 and Figure 2 above. In Experiment 1, the student releases a ball from rest and uses a slow-motion camera to film the ball as it falls to the ground. Using video analysis, the student is able to plot the ball's horizontal position x and vertical position y as a function of time t. In Experiment 2, the student horizontally rolls the same ball off a table, and uses video analysis to plot the ball's horizontal position x and vertical position y as a function of time t starting from the instant the ball leaves the table. The graphs from each experiment are shown above along with each graph's best-fit curve line. 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.

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.

The force diagram above shows a box accelerating to the right on a horizontal surface of negligible friction. The tension T is exerted at an angle of 30° above the horizontal. If μ is the coefficient of kinetic friction between the box and the surface, which of the following is a correct mathematical equation derived by applying Newton's second law to the box?

d) a=Tcos(θ)−μ(Mg−Tsin(θ)/m

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 carts 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

A student wants to launch a toy dart toward a target that hangs from a light string. At time t=0, the dart is launched with an initial speed v0 at an angle θ0 above the horizontal ground. At the instant the dart is launched, the string is cut such that the target begins to fall straight down. The positive horizontal direction is considered to be to the right, and the positive vertical direction is considered to be up. 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 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 indicated by which of the following?

e) (arrow pointing to the center of circle)

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) 1/16W

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 throwers 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

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. An object is thrown with an initial speed u near the surface of 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

an object is thrown with an initial speed V near the surface of the earth. Assume that air resistance is negligible in the gravitational field is constant. If the object is thrown vertically upward, the direction and magnitude of its acceleration while in the air is a) upward and decreasing b) upward in constant c) downward and decreasing d) downward and increasing e) downward and constant

e) downward and constant