AP Physics 1 Momentum

A ball of mass M and speed v collides head-on with a ball of mass 2M and speed v/2, as shown above. If the two balls stick together, their speed after the collision is

0

A block of mass 3 kg slides along a horizontal surface that has negligible friction except for one section, as shown above. The block arrives at the rough section with a speed of 5 m/s and leaves it 0.5 s later with a speed of 3 m/s. What is the magnitude of the average frictional force exerted on the block by the rough section of the surface?

12 N

A ball of mass m and momentum p has kinetic energy equal to which of the following?

1p^s/2m

A ball of mass 0.4 kg is initially at rest on the ground. It is kicked and leaves the kicker's foot with a speed of 5.0 m/s in a direction 60° above the horizontal. The magnitude of the impulse imparted by the ball to the foot is most nearly

2 N▪s

Two objects of mass 0.2 kg and 0.1 kg, respectively, move parallel to the x-axis, as shown above. The 0.2 kg object overtakes and collides with the 0.1 kg object. Immediately after the collision, the y-component of the velocity of the 0.2 kg object is 1 m/s upward. What is the y-component of the velocity of the 0.1 kg object immediately after the collision?

2 m/s downward

Two objects, A and B, initially at rest, are "exploded" apart by the release of a coiled spring that was compressed between them.As they move apart, the velocity of object A is 5 m/s and the velocity of object B is -2 m/s. The ratio of the mass of object A to the mass of object B, mA/mB, is

2/5

A block of mass 3 kg slides along a horizontal surface that has negligible friction except for one section, as shown above. The block arrives at the rough section with a speed of 5 m/s and leaves it 0.5 s later with a speed of 3 m/s. What is the magnitude of the work done by the frictional force exerted on the block by the rough section of the surface?

24 J

The two blocks of masses M and 2M shown above initially travel at the same speed v but in opposite directions. They collide and stick together. How much mechanical energy is lost to other forms of energy during the collision?

4/3 Mv^2

A student obtains data on the magnitude of force applied to an object as a function of time and displays the data on the graph above. Answer the following question for the information and diagram above. The increase in the momentum of the object between t = 0 s and t = 4 s is most nearly

60 N·s

Block 1 of mass m1 and block 2 of mass m2 are sliding along the same line on a horizontal frictionless surface when they collide at time tc. The graph above shows the velocities of the blocks as a function of time. Which block has the greater mass, and what information indicates this?

Block 2, because the final velocity is closer to the initial velocity of block 2 than it is to the initial velocity of block 1.

A force of constant magnitude F and fixed direction acts on an object of mass m that is initially at rest. If the force acts for a time interval ∆t over a displacement ∆x , what is the magnitude of the resultant change in the linear momentum of the object?

F ∆t

Three objects can only move along a straight, level path. The graphs below show the position d of each of the objects plotted as a function of time t. The magnitude of the momentum of the object is increasing in which of the cases?

III only

Block 1 of mass m1 and block 2 of mass m2 are sliding along the same line on a horizontal frictionless surface when they collide at time tc. The graph above shows the velocities of the blocks as a function of time. How does the kinetic energy of the two-block system after the collision compare with its kinetic energy before the collision, and why?

It is less, because the blocks have the same velocity after the collision, so some of their kinetic energy was transformed into internal energy.

How does an air mattress protect a stunt person landing on the ground after a stunt?

It lengthens the stopping time of the stunt person and reduces the force applied during the landing.

Which of the following is true of the conservation of momentum and kinetic energy?term-0

Kinetic energy is conserved only in elastic collisions.

Two skaters are initially at rest next to each other on frictionless ice. Skater A pushes on skater B. If skater A has greater mass than skater B, which of the following correctly relates the magnitudes of their momentums p and their kinetic energies K after the push?

Pa = Pb and Ka < Kb

A railroad car of mass m is moving with speed u when it collides with and connects to a second railroad car of mass 3m, initially at rest, as shown above. How do the speed and kinetic energy of the connected cars compare to those of the single car of mass m before the collision?

Speed Kinetic Energy Less Less

Two people of unequal mass are initially standing still on ice with negligible friction. They then simultaneously push each other horizontally. Afterward, which of the following is true?

The momenta of the two people are of equal magnitude.

A solid metal ball and a hollow plastic ball of the same external radius are released from rest in a large vacuum chamber. When each has fallen 1 m, they both have the same

speed

An empty sled of mass M moves without friction across a frozen pond at speed v0. Two objects are dropped vertically into the sled one at a time: first an object of mass m and then an object of mass 2m. Afterward the sled moves with speed vf. What would be the final speed of the sled if the objects were dropped into it in reverse order?

vf