**A particle of mass m moving at 5.0 m/s in the positive x direction makes a glancing elastic collision with a particle of mass 2m that is at rest before the collision. After the collision, m moves off at an angle of 45º to the x axis and 2m moves off at 60º to the x axis. The speed of m after the collision is? SHOW WORK
momentum is conserved, and the kinetic energy after the collision is less than its value before the collision.
C)
momentum is conserved, and the kinetic energy after the collision is the same as the kinetic energy before the collision.
D)
momentum is not conserved, and the kinetic energy of the system after the collision differs from the kinetic energy of the system before the collision.
E)
the kinetic energy of the system after the collision depends on the masses of the objects.
_____8.
*A car having a total mass of 2250 kg and traveling at 72.0 km/h smashes into a tree. The car is stopped in 0.250 s. The average force acting on the car during the collision is? SHOW WORK
A)
1.80 105 N
B)
80.0 N
C)
1.80 102 N
D)
Zero
E)
2.20 104 N
_____9.
*Using a mallet, you strike a ball of mass 0.50 kg that is initially at rest. The force F on the ball as a function of time is plotted in the figure. At t = 2.0 ms, the speed of the ball is? SHOW WORK
A)
10 m/s
B)
8.0 m/s
C)
6.0 m/s
D)
4.0 m/s
E)
2.0 m/s
_____10.
**A projectile with a mass 6kg is fired at a speed of 400 m/s at an angle of 60º above the horizontal. At the highest point of its trajectory, the projectile is broken into two equal pieces by an internal explosion. Just after the explosion, one of the two pieces is known to be traveling vertically downward at a speed of 300 m/s. The magnitude of the velocity of the other half of the projectile is? SHOW WORK
A)
500 m/s
B)
1.50 km/s
C)
400 m/s
D)
710 m/s
E)
123 m/s
_____11.
**A 20-g bullet is fired into a 2.0-kg block of wood placed on a horizontal surface. The bullet stops in the block. The impact moves the block (+ bullet) a distance of 5 m before it comes to rest. If the coefficient of kinetic friction between the block and surface is 0.25, calculate the speed of the bullet as it is fired from the gun. SHOW WORK
A)
200 m/s
B)
350 m/s
C)
250 m/s
D)
500 m/s
E)
220 m/s
_____12.
**A bullet, m = 0.500 kg, traveling with a velocity of vb strikes and embeds itself in the bob of a ballistic pendulum, M = 9.50 kg. The combined masses rise to a height h = 2 m while friction in the pendulum takes out 49 J of energy during the swing. The speed vbof the bullet is? SHOW WORK
