1. Compare the momentum of a 1-ton car moving at 100 km/h with a 2-ton truck moving at 50 km/h.
2. Does a moving object have impulse?
3. Does a moving object have momentum?
4. For the same force, which cannon imparts a greater impulse to a cannonball—a long cannon or a short one?
1. Both have the same momentum (1 \text { ton } \times 100 km / h =2 \text { ton } \times 50 km / h ).
2. No, impulse is not something an object has, like momentum. Impulse is what an object can provide or what it can experience when it interacts with some other object. An object cannot possess impulse just as it cannot possess force.
3. Yes, but like velocity, in a relative sense—that is, with respect to a frame of reference, usually Earth’s surface. The momentum possessed by a moving object with respect to a stationary point on Earth may be quite different from the momentum it possesses with respect to another moving object.
4. The long cannon will impart a greater impulse because the force acts over a longer time. (A greater impulse produces a greater change in momentum, so a long cannon will impart more
speed to a cannonball than a short cannon.)