Worksheet 140 - Even More Collisions
(Smashing!!!- Sorry- It was just an Impulse)
H020110B
1. How much momentum does a 78 kg running back have if he is running at 6.5
m/s? How fast must a 54 kg cross-country runner run if she is to have the same
momentum as the running back?
2. A 2400 kg truck has a momentum of 33,000 kg*m/s. How fast is it traveling?
3. A projectile has a kinetic energy of 180 J. If it has a mass of 0.012 kg, how much
momentum does this projectile have?
4. Ace Daring, intergalactic Space Superhero, is flying throughout the reaches of
the known universe in his highly experimental supersonic interstellar
hyperspace turbo-boosted rocket ship when he reaches an unexplored section of
space. He detects a strangely varying energy field which provides his ship with
an unexpected impulse. The mass of his ship is 560,000 kg, and he is initially
cruising with a velocity of 2 * 105 m/s. Over a time of 24 s, his ship experiences a
net force of 9.1 * 107 N. What is this impulse, and what is the final speed of his
rocket ship after entering this strange region?
5. A tennis ball is thrown against a wall and strikes it with an initial velocity of +15
m/s. The ball rebounds in the opposite direction with a final velocity of -13.8
m/s. If a tennis ball has a mass of 0.045 kg, what is the impulse delivered to the
wall? How much kinetic energy is lost in this collision?
6. A 1800 kg car accelerates from rest for 7.2 s with an acceleration of 3.4 m/s 2.
What is the impulse delivered to the car? What is the car’s final velocity?
7. A 0.084 kg baseball is pitched with an initial velocity of +36 m/s when it is struck
by a bat. The ball and bat are in contact for a duration of 0.0025 s. The ball
leaves the bat with a velocity of -41.5 m/s. What is the net force that acts on the
ball? Assume the baseball is constantly moving only in 1 dimension
8. A 0.5 kg dynamics cart is initially at rest. A second 1.0 kg dynamics cart is given
an initial velocity of +2.5 m/s towards the first. As a result of the collision, the
second cart has a final velocity of +1 m/s. What is the final velocity of the first
cart? Is this collision perfectly elastic?
9. While sitting at a stoplight, an unobservant driver in a 1600 kg car strikes a 2400
kg truck that is initially at rest. After a completely inelastic collision, the
vehicles move forward with a velocity of 6.2 m/s. What was the initial velocity of
the car?
10. I have designed and developed a method for determining the speed of a
projectile using conservation of momentum and collisions. In this method, a
projectile is fired into a large catching device that is initially at rest. The speed
after the collision is carefully measured. Assuming a completely inelastic
collision, it is not difficult to find the initial velocity of the projectile.
In one particular test, a 0.002 kg object is fired with unknown velocity into a 2.7
kg catching device. Immediately after the collision takes place, it is observed
that the two objects (the projectile is now imbedded in the catching device) move
with a final velocity of 0.32 m/s. What is the initial velocity of the projectile?
11. * A 1495 kg car is initially driving at 20 m/s due East (zero degrees) when it is
struck by a 1936 kg SUV driving 24 m/s due North (90 degrees). The two objects
undergo a completely inelastic collision. What is the final velocity of the
vehicles? [Hint: find the final velocity in the x-direction, the final velocity in the ydirection, and use the Pythagorean theorem to find vf.]
12. A rocket consist of two parts. Ma has a mass of 1200 kg and Mb has a mass of
1800 kg. Explosive bolts now separate the two pieces with providing an impulse
of 300 n sec to both sections of the rocket. What is the relative velocity between
the two sections after the explosion?
13. A block of wood has a mass of 5 kg and is traveling at a velocity of
10 m/sec @ 0o. A lump of silly putty has a mass of 2 kg and has a velocity of
20 m/sec @ 90o. It these two masses inelastically collide, what is the final velocity
vector of the resulting wood/putty mess?