MIAT Physics Practice Test

Impulse is the change in momentum. Since momentum is p = m v, the change in momentum is Δp = p_f − p_i = m v_f − m v_i = m (v_f − v_i). So the impulse delivered is J = m (v_f − v_i). The other expressions mix momentum or average values instead of the actual change, which is why they don’t match the impulse. If you treat velocities as vectors, J is the vector difference scaled by the mass, and its magnitude is |J| = m |v_f − v_i| when directions matter.