21. A miniature spring-loaded, radio-controlled gun mounted an air puck. : 2102136
21. A miniature spring-loaded, radio-controlled gun is mounted on an air puck. The gun's bullet has a mass of 5.00 g, and the gun and puck have a combined mass of 120 g. With the system initially at rest, the radio controlled trigger releases the bullet causing the puck and empty gun to move with a speed of 0.500 m/s. What is the bullet's speed?
A. 4.80 m/s
B. 11.5 m/s
C. 48.0 m/s
D. 12.0 m/s
22. A uranium nucleus (mass 238 units) at rest decays into a helium nucleus (mass 4.0 units) and a thorium nucleus (mass 234 units). If the speed of the helium nucleus is 6.0 ´ 105 m/s, what is the speed of the thorium nucleus?
A. 1.0 ´ 104 m/s
B. 3.0 ´ 104 m/s
C. 3.6 ´ 104 m/s
D. 4.1 ´ 104 m/s
23. If the momentum of an object is tripled, its kinetic energy will change by what factor?
24. The kinetic energy of an object is quadrupled. Its momentum will change by what factor?
25. A moderate force will break an egg. However, an egg dropped on the road usually breaks, while one dropped on the grass usually doesn't break. This is because for the egg dropped on the grass:
A. the change in momentum is greater.
B. the change in momentum is less.
C. the time interval for stopping is greater.
D. the time interval for stopping is less.