Question

A boy sits on a boat in a lake. In his boat he has a pile of rocks, each with mass 0.538 kg. He throws the rocks off the back of the boat at a rate of one rock every 0.964 sec, with a horizontal velocity of 11.6 m/s. What is the thrust on the boat from this "rock-throwing propulsion"? That is, what is the magnitude of the average force experienced by the boat during this process?

Answer 1

Answer:

6.47385 N

Explanation:

m = Mass of stone = 0.538 kg

t = Time taken to hit the rock = 0.964 seconds

v = Velocity of rock = 11.6 m/s

Force is given by

$F=\frac{mv}{t}\\\Rightarrow F=\frac{0.538\times 11.6}{0.964}\\\Rightarrow F=\frac{6.2408}{0.964}\\\Rightarrow F=6.47385\ N$

The magnitude of the average force experienced by the boat during this process is 6.47385 N