首先定义所谓“打得重”:时间相同,impulse越大打的越“重”。
impulse = dF/dt
according to conservation of linear impulse, L1+impulse = L2
L is the linear momentum of the system of the bar and the objective that is being hit.
L2 is the linear momentum of the system after the strike, assuming both the bar and the objective are not moving after the strike.
assuming we are striking the bar with the same velocity, in the second scenario, the velocity of the bar should be larger than that in the first scenario.
If we assume the striking time is the same, the impulse of the 2 case(on the motorcycle) should be higher. In other words, 打得更重
所以在摩托车上打人会打得更重, 但不是因为惯性力的原因, 是因为impulse更大