A water jet is releasing water at the rate of 1.5kg/s and at a speed of 1m/s is focused normally on a 2kg block moving with a uniform velocity 2m/s.The jet is focused in opposite to the motion of the block the speed of the block after the jet is focused for 10seconds is
A) 4.5m/s B)9.5m/s C )7.5m/s D)5.5m/s
net impulse of water:
mass*velocity= 1m/s*1.5kg/sec*10sec
assuming water does not stick to the block, and falls with zero horizontal velocty
final momentum block=initialmomentum+impulse
2*Vf=2*2-1*1.5*10
a negative sign in vf indicates opposite direction to intial velocity.