Question

a 5 kg block is resting on a friction less plane . it is struck by a jet releasing water at the rate of 4kg/s emerging with a speed of 5m/s calculate the initial acceleratin of the block (in m/s²)​

Answer 1

a 5 kg block is resting on a friction less plane . it is struck by a jet releasing water at the rate of 4kg/s emerging with a speed of 5m/s calculate the initial acceleratin of the block (in m/s²)

solution : The jet releasing water at the rate of , dm/dt = 4kg/s

so, mass of water after time t, m = t × dm/dt = 4t kg

speed of water , v = 5m/s

so, force exerted by water , F = ma = m(v/t)

= 4t × 5/t = 20N

now, acceleration of block of mass 5kg , a = F/M = 20N/5kg = 4m/s²

hence, acceleration of block is 4m/s²