Answer:
The magnitude of the change in momentum of the stone is 5.51kg*m/s.
Step-by-step explanation:
the final kinetic energy = 1/2(0.15)v^2
1/2(0.15)v^2 = 70%*1/2(0.15)(20)^2
v^2 = 21/0.075
v^2 = 280
v = 16.73 m.s
if u is the initial speed and v is the final speed, then:
u = 20 m/s and v = - 16.73m/s
change in momentum = m(v-u)
= 0.15(- 16.73-20)
= -5.51 kg*m.s
Therefore, The magnitude of the change in momentum of the stone is 5.51kg*m/s.