Question

What is the difference between impulse and impulsive force? Explain.

Answer 1

If I push on an object with a force \( F \) for a period of time \( t \), then I give the object an impulse, \( I \) which changes the objects momentum. In fact, the impulse \( I \) is exactly change of momentum and it can be calculated by multiplying force and time:
\[ I = F \ t \]

You can see this is change in momentum because, \( F = ma \) and therefore
\[ I = F t = m (at) = m (v_2 - v1) \]
the last step \( at = v_2 - v_1 \) follows from the definition of acceleration.