Ap Physics tri 2 Final
The graph above shows the position x as a function of time for the center of mass of a system of particles of total mass 6.0 kg. For a very short time interval around 2.0 s, an external force is exerted on an object in the system. What is the resulting change in momentum of the system?
-18 kg×m/s
a block of mass 10 kg moves from position a to position b shown in figure above.The speed of the block is 10 m/s at a and 4m/s at b. Th work done on block as it moves is nearly
-220J
A 1.0 kg lump of clay is sliding to the right on a frictionless surface with speed 2 m s . It collides head-on and sticks to a 0.5 kg metal sphere that is sliding to the left with speed 4 m s . What is the kinetic energy of the combined objects after the collision?
0 J
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
A student is asked to determine the work done on a block of wood when the block is pulled horizontally using an attached string. The student is supplied with a spring scale, a stopwatch, and a meterstick. Which of the following graphical analysis techniques will allow the student to determine the work done on the block by the string?
Graphing the force as a function of distance and calculating the area under the curve
Some bicycle brakes work by pressing rubber pads against the rim of the wheel. To test newly designed brakes, bicycle engineers mount a wheel of known rotational inertia on a low-friction axle, as shown above. The engineers spin the wheel with known initial angular speed and then apply the brakes with a constant force. Which of the following procedures would enable the engineers to find the torque exerted by the brakes on the wheel? Select two answers.
Measuring how much time the wheel takes to come to rest or Measuring how many rotations the wheel completes while coming to rest
The figure above shows a uniform beam of length L and mass M that hangs horizontally and is attached to a vertical wall. A block of mass M is suspended from the far end of the beam by a cable. A support cable runs from the wall to the outer edge of the beam. Both cables are of negligible mass. The wall exerts a force FW on the left end of the beam. For which of the following actions is the magnitude of the vertical component of FW smallest?
Moving both the support cable and the block to the center of the beam
Two blocks are connected to identical ideal springs and are oscillating on a horizontal frictionless surface. Block A has mass m, and its motion is represented by the graph of position as a function of time shown above on the left. Block B's motion is represented above on the right. Which of the following statements comparing block B to block A is correct?
Because block B has more mass, its acceleration is smaller than that of block A at any given displacement from the equilibrium position.
A stone of a mass (m) is thrown upward at a 30⁰ angle to the horizontal. At the instant the stone reaches its highest point, why is the stone neither gaining nor losing speed?
Because the angle between the stone's velocity and the net force exerted upon the stone is 90⁰
Using a force probe, a student generates the graph above of the force exerted on a small wagon as a function of time. The wagon starts from rest and rolls with negligible friction in the axles. Which of the following graphs best represents the wagon's momentum as a function of time?
D- parabolic curve upwards
The figure above represents the orbit of two planets of equal masses that orbit their star in the counter clockwise direction as a double planet system. From the point of view as an observer on either planet, the planets appear to be orbiting around each other as we as the star. the dots on the orbits represent the position of the planet at time t0 and X is the position of there center of mass at that time. Which arrow represents the acceleration of the center of mass of the double planet system at point X
southwest arrow
Which of the following graphs best represents the force Fnet exerted on the two ship system
straight line going from bottom left to top right
A solid metal bar is at rest on a horizontal frictionless surface. It is free to rotate about a vertical axis at the left end. The figures below show forces of different magnitudes that are exerted on the bar at different locations. In which case does the bar's angular speed about the axis increase at the fastest rate?
the bar with the F at the end upwards
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 total mechanical energy of the Earth-book system?
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
The data in the table below were recorded during an experiment in which two carts on a frictionless one-dimensional track collide head-on. What are the values of the magnitude of the change in momentum ∆p2 of cart 2 and the magnitude of its average acceleration a2 during the collision? Cart 1 Cart 2 Mass 5 kg 1 kg Average Force 15 N 15 N Change in Momentum 0.3 kg×m/s ∆p2 Average Acceleration 3 m/s2 a2
∆p2- 0.3 kg×m/s and a2- 15 m/s²
Which of the following correctly ranks the displacement ∆x for the three segments of the object's motion?
∆x3 > ∆x1 > ∆x 1> 0
Two identical blocks with mass 5.0 kg each are connected to the opposite ends of a compressed spring. The blocks initially slide together on a frictionless surface with velocity 2 m s to the right. The spring is then released by remote control. At some later instant, the left block is moving at 1 m s to the left, and the other block is moving to the right. What is the speed of the center of mass of the system at that instant?
2 m/s
Planet X has twice Earth's mass and three times Earth's radius. The magnitude of the gravitational field near plant X's surface is most nearly
2N/kg
The magnitude of the gravitational field on the surface of a particular planet is 2g. The planet's mass is half the mass of Earth. What is the planet's radius in terms of the radius RE of Earth?
RE/2
A 0.050 kg tennis ball is moving to the left at 10 m s when it is hit by a tennis racket that is moving to the right. The magnitude of the force exerted on the ball by the racket as a function of time is shown in the figure above. What is the speed of the ball after the collision with the racket?
30 m/s
The graph above shows the change in linear momentum of the sphere of mass (m) as a function of time. What is the linear momentum of the two-sphered system at time (t=3.0)
15 kg*m/s
Object A has mass 2 kg and is traveling to the right at speed 3 m/s. Object B is traveling to the left at 3 m/s. The objects collide head-on, and afterward each has a speed of 3 m/s. Which of the following could be the mass of object B ? Select two answers.
2 kg and negligible compared to 2 kg
An object with mass m is suspended at rest from a spring with a spring constant of 200 N m . The length of the spring is 5.0 cm longer than its unstretched length L, as shown above. A person then exerts a force on the object and stretches the spring an additional 5.0 cm. What is the total energy stored in the spring at the new stretched length?
1.0 J
A 50 kg athlete running at speed v grabs a light rope that hangs from a 10-meter-high platform and swings to a maximum of 1.8 m above the ground. Later, a 100 kg athlete, running at the same speed, grabs a similar rope hanging from a 5-meter-high platform. What is the maximum height to which the 100 kg athlete swings?
1.8 m
To analyze the characteristics and performance of the brakes on a 1500 kg car, researchers collected the data shown in the table above. It shows the car's speed when the brakes are first applied and the corresponding braking distance required to stop the car. The magnitude of the average braking force on the car is most nearly
12,000 N
For another identical object initially at rest, no frictional force is exerted during segment 2 (between t = 2 s and t = 4 s). A rope exerts the same constant force of magnitude FT as in the previous scenario. What is the change in the object's kinetic energy during segment 2?
12.0 J
A force (F) is exerted on a 5kg block to move it across a rough surface, as shown above. The magnitude of the force is initially 5 N, and the block moves at a constant velocity. While the block is moving, the force is instantaneously increased to 12 N. How much kinetic energy does the block now gain as it moves a distance of 2 m?
14J
a planet is in a elliptical orbit around a star as shown above which of the following best represents the mechanical energy E planet of just the planet and the mechanical energy E star-planet of the star planet system as a function of time for one complete orbit
Curved line above x axis and flat line below x axis
A cart of known mass moves with known speed along a level, frictionless track, as shown in the figure above. The cart hits a force sensor and rebounds. The force sensor measures the force exerted on the cart as a function of time and as a function of the position of the cart. The results will be graphed on the axes shown. Which of the two graphs can be used to determine the cart's speed after it rebounds?
Either graph 1 or graph 2 can be used (graphs are time vs f or postion vs f
Which of the following expressions correctly relates the magnitudes Ff and FT ?
FT < Ff < 2 FT
A disk of known radius and rotational inertia can rotate without friction in a horizontal plane around its fixed central axis. The disk has a cord of negligible mass wrapped around its edge. The disk is initially at rest, and the cord can be pulled to make the disk rotate. Which of the following procedures would best determine the relationship between applied torque and the resulting change in angular momentum of the disk?
For five forces of different magnitude, pulling on the cord for 5 s, and then measuring the final angular velocity of the disk
The pendulum shown in the figure above reaches a maximum height h above the equilibrium position as it oscillates. Assuming friction and air resistance are negligible, which of the following is true about the total energy of the Earth-pendulum system as the pendulum oscillates?
It is constant throughout the pendulum's motion.
An ice-skater is moving at a constant velocity across an icy pond. The skater throws a snowball directly ahead. Which of the following correctly describes the velocity of the center of mass of the skater-snowball system immediately after the snowball is thrown? Assume friction and air resistance are negligible.
It is equal to the original velocity of the skater
A 2kg object traveling at 5m/s on a frictionless horizontal surface collides head on with and sticks to a 3kg object initially at rest. Which of the following correctly identifies the change in total kinetic energy and the resulting speed of the objects after the collision?
Kinetic energy: decreases Speed: 2m/s
A pendulum consisting of a sphere suspended from a light string is oscillating with a small angle with respect to the vertical. The sphere is then replaced with a new sphere of the same size but greater density and is set into oscillation with the same angle. How do the period, maximum kinetic energy, and the maximum acceleration of the new pendulum compare to those of the original pendulum?
Period: the same Maximum Kinetic energy: larger Maximum Acceleration: the same
Some students want to calculate the work done by friction as an object with unknown mass moves along a straight line on a rough horizontal surface. The students have a force probe, a meter stick, and a stopwatch. Which of the following will allow the students to take the measurements needed to calculate the work done by friction?
Pulling the block at an unknown constant speed with the force probe for a measured distance
Which of the following best explains why the system does not rotate around its center of mass as it falls
The earth exerts a larger gravitational force on the sphere of mass 2m, but that sphere is closer to the center of mass and the torques cancel out
An athlete with mass (m) running at speed (v) grabs a light rope that hangs from a ceiling of height (H) and swings to a maximum height of h₁. In another room with a lower ceiling of height H/2, a second athlete with mass 2m running at the same speed (v) grabs a light rope hanging from the ceiling and swings to a maximum height of h₂. How does the maximum height reached by the two athletes compare and why?
The two athletes reach the same height because the athletes run with the same speed
Does at least one of the ships have its engine turned on during the time interval shown and what evidence indicates so
Yes because the momentum of the two rocket system increases
A stone disk is sliding on frictionless ice to the west with speed v, as shown in the figure above. As the disk slides by, a child uses a rubber mallet to hit the disk at point X, exerting a force directly toward the center of the disk. The child hits point X every half second for about 10 s, changing the trajectory of the disk but not causing it to rotate. Which of the following most closely approximates the path of the disk while the child is hitting it?
a parabolic path
A ball attached to a light string swings in a counterclockwise vertical circle, as shown above. Which of the following arrows represent one of the forces exerted on the ball at the moment it passes through point P ? Select two answers.
↓ and ←
Ahhh (target thing)
dots starting at the bottom left corner and going up to the right
In a one-dimensional perfectly elastic collision, an object of mass m is traveling with speed v0 in the +x-direction when it strikes an object with mass 3m that is at rest. What are the objects' velocities following the collision?
m-v0/2, -x-direction, 3m- v0/2, +x-direction
Two identical blocks are connected to the opposite ends of a compressed spring. The blocks initially slide together on a frictionless surface with velocity (v) to the right. The spring is then released by remote control. At some later instant the left block is moving at v/2 to the left, and the other block is moving to the right. What is the speed of the center of mass of the system at that instant?
v
