Question

A rope is stretched between two boats at rest. A sailor in the first boat pulls the rope with a constant force of 100 N. First boat with the sailor has a mass of 250 kg whereas the mass of second boat is double of this mass. If the initial distance between the boats was 100 m, the time taken for two boats to meet each other in seconds is (neglect water resistance between boats and water). Answer the nearest integer.

Answer 1

The force of 100 N acts on both the boats $250a_1=100and500a_2=100$
or $a_1=0.4m{s}^{-2}and{a}_2=0.2m{s}^{-2}$
Relative acceleration: $a=a_1+a_2=0.6m{s}^{-2}$
Using $S=ut+\frac{1}{2}a{t}^2,weget$
$100=\left(1/2\right)\times 0.6\times t^{2}ort=18.3s$