Terms to Know
What is the unit of momentum?
kg * m/s
A 9.00 * 104 kg rocket is in space facing the sun. To move towards the sun, its engine exhausts propellant at a mass flow rate of 1.00 * 102 kg/s with a speed of 3.0 * 103 m/s.
What is the initial acceleration of the rocket?
3.33 m/s2
What is a measure of the change in momentum of a system?
Impulse
.529 m/s south
What is the only way to change the momentum of an object in angular motion?
Changing the torque applied to the system
Two physics students conduct a collision experiment with two gliders on a frictionless air track. One student starts a 50.0 g glider at 1.24 m/s to the right. The other student starts a 75.0 g glider to the left at 2.15 m/s. What are the velocities of each after the elastic collision, assuming no friction?
Glider 1: 2.82 m/s
Glider 2: .6 m/s
(Worked out solution on pg. 232-233)
In a two-dimensional collision, which collision makes the largest angle after the collision?
Elastic (angle is smaller as the collision is less elastic)
A 90 kg object is at rest when is explodes into three fragments. Fragment 1 (31 kg) travels on the negative x-axis at 100 m/s. Fragment 2 (47 kg) travels at 40o above the positive y-axis at 87 m/s.
What is the velocity of the third fragment?
218.9 m/s at 89.30 below the negative x-axis
Define elastic, partially elastic, and inelastic collisions.
Elastic - only conservative forces act; total mechanical energy, momentum, and kinetic energy is conserved
Partially elastic - one or more of the colliding masses is partially deformed. Momentum is conserved, but kinetic energy is not
Inelastic - the colliding masses stick together, kinetic energy is not conserved
A 975 kg car travels northeast at 8.15 m/s.
a. What is the car's momentum?
b. What impulse is needed to stop the car?
c. What force is needed to stop the car in 10.0 s?
a. 7.59 * 103 kg*m/s
b. -7.95 * 103 kg*m/s
c. -795 N