✔ 最佳答案
Let the initial velocity of P be vP m s-1,
and the initial velocity of Q be vQ m s-1.
Initial momentum of P = (1) vp = vP kg m s-1
Initial momentum of Q = (2) vQ = 2vQ kg m s-1
Initial momentum of P = Initial momentum of Q
vP = 2vQ
Let the constant resisting force be F N.
Let the stopping distance of P be sP m,
and the stopping distance of Q be sQ m.
To stop the object P:
Work done by the resisting force = Initial K.E. of P
F sP = (1/2) (1) (vp)2
F sP = (1/2) (1) (2vQ)2
sP = 2(vQ)2
To stop the object Q:
Work done by the resisting force = Initial K.E. of Q
F sQ = (1/2) (2) (vQ)2
SP = (vQ)2
(Stopping distance of P) : (Stopping distance of Q)
= sP : sQ
= 2(vQ)2 : (vQ)2
= 2 : 1
=
