1. A 2500 kg car traveling to the North is slowed down uniformly from an initial velocity of 20 m/s by a 6,250 N braking force acting opposite the car’s motion.
a) What is the car’s velocity after 2.5 seconds?
b) How far does the car move during 2.5 seconds?
c) How long does it take for the car to come to a complete stop?
2. A 47.4 kg student runs down the sidewalk and jumps with a horizontal speed of 4.20 m/s onto a stationary skateboard. The student and skateboard move down the sidewalk with a speed of 3.95 m/s. Find the following:
a) the mass of the skateboard.
b) how fast the student would have to jump to have a final speed of 5 m/s.
c) the energy loss that occurred during part “b” above.
3. High-speed stroboscopic photographs show the head of a 215 gram golf club traveling at 55 m/s just before it strikes a 46g golf ball at rest on a tee. After the collision, the club travels (in the same direction) at 42 m/s. find the speed of the golf ball just after impact. Was the collision Elastic or Inelastic. Fully explain your rationale.
4. A billiard ball of mass 200g rolls toward the right-hand cushion of a billiard table at 2 m/s and rebounds straight back at 2 m/s.
a) What is the change in momentum as a result of hitting the cushion?
b) What impulse is given to the ball by the cushion?
5. A hockey puck of mass 0.20 kg is sliding along a smooth, flat section of ice at 18 m/s when it encounters some snow. After 2.5 seconds of sliding through the snow, it returns to smooth ice, continuing at a speed of 10 m/s.
a) What is the change of momentum of the puck?
b) What impulse does the snow exert on the puck?
c) What average frictional force does the snow exert on the puck?
6. A 3 meter long pendulum with a 4 kg bob on its end is loaded to a 50o angle and then released. At the bottom of its swing it collides head on and elastically with a 500 gram object. Find the speed of the 500 gram object after the collision, as well as the angle that the pendulum bob will rise back to after the collision.
7. A force of 5 Newtons directed South is applied for 10 seconds to a 4 kg object that is moving at 4 m/s Northeast. Find the final velocity of the object after these 10 seconds.
8. A 10,000 kg truck traveling at 30 m/s [N 40o E] collides with a 1,500 kg car traveling at 45 m/s [S 20 o W]. If the cars stick together, find their velocity (magnitude and direction) after the collision.
9. The graph at the right shows the magnitude of the retarding force exerted to an object to slow it down during a collision. If the object has a mass of 50 kg and is traveling at 10 m/s before the collision, find:
a) the total impulse delivered to the object.
b) the final speed of the object.
c) the speed of the object after 12 seconds.
d) the object’s momentum after 14 seconds.
10. A 10 kg bomb explodes into 4 pieces. The first 2 kg piece travels South at 50 m/s.
The second 3 kg piece travels West at 35 m/s. The third 1 kg piece travels northeast at
40 m/s. Find the velocity (magnitude and direction) of the final piece.
11. A 4kg block is sliding on a frictionless surface at 8 m/s toward a hill whose angle of inclination is 40o. It is suddenly rear-ended by a 10 kg block that is moving at 12 m/s. The collision is NOT elastic, but is also NOT perfectly inelastic, and the 10 kg block continues moving forward, but slows down to 10 m/s after the collision. Find the distance that the 4kg block will travel up the hill.
12. A 6 kg block sits at rest (on a flat surface) against an uncompressed spring of spring constant 10,000 N/m. A 2 kg block slides toward the spring at a speed of 10 m/s and collides ELASTICALLY with the 6kg block. Find the velocity of the 2kg block after the collision as well as the amount that the spring will be compressed.
All answers (and full solutions) can be found on Mr. L’s website J