# Momentum

1. What is the mass of a very large ship that has a momentum of $1.60 \times 10^9$ kg · m/s , when the ship is moving at a speed of 48.0 km/h?
2. What is the momentum of  2000-kg elephant charging a hunter at a speed of 7.50 m/s?
3.  A bullet is accelerated down the barrel of a gun by hot gases produced in the combustion of gun powder. What is the average force exerted on a 0.0300-kg bullet to accelerate it to a speed of 600 m/s in a time of 2.00 ms (milliseconds)?
4. If the momentum of a spacecraft if given by $\vec{p}(t) = 5t\hat{x} + 7 t^2 \hat{y}$, what is the force that acts on the spacecraft as a function of time?
5. Train cars are coupled together by being bumped into one another. Suppose two loaded train cars are moving toward one another, the first having a mass of 150,000 kg and a velocity of 0.300 m/s, and the second having a mass of 110,000 kg and a velocity of −0.120 m/s . (The minus indicates direction of motion.) What is their final velocity?
6. Suppose a clay model of a koala bear has a mass of 0.200 kg and slides on ice at a speed of 0.750 m/s. It runs into another clay model, which is initially motionless and has a mass of 0.350 kg. Both being soft clay, they naturally stick together. What is their final velocity?
7. Sometimes in movies, you’ll see someone fire a shotgun and then be blown back by the recoil.  If a typical shotgun shoots 28.3g of pellets and the pellets  have velocities of 550m/s what velocity would momentum conservation give to a 50kg person who fires a shotgun?
8. During an ice show, a 60.0-kg skater leaps into the air and is caught by an initially stationary 75.0-kg skater. (a) What is their final velocity assuming negligible friction and that the 60.0-kg skater’s original horizontal velocity is 4.00 m/s? (b) How much kinetic energy is lost?
9. Two satellites approach one another, the first with a speed of 0.250 m/s and the second at rest, intending to dock. The first has a mass of 4000kg , and the second a mass of 7500kg . If the two satellites collide elastically instead of docking what is the final velocity of the two satellites?