# A car of mass  is initially at rest on the boat of mass  tied to the wall of dock through a massless, inextensible string. The car accelerates from rest to velocity  in times . At  the car applies brake and comes to rest relative to the boat in negligible time. Neglect friction between the boat and water; the time  at which boat will strike the wall is a) b) c) d) None of these

## Question ID - 100504 | SaraNextGen Top Answer A car of mass  is initially at rest on the boat of mass  tied to the wall of dock through a massless, inextensible string. The car accelerates from rest to velocity  in times . At  the car applies brake and comes to rest relative to the boat in negligible time. Neglect friction between the boat and water; the time  at which boat will strike the wall is a) b) c) d) None of these

1 Answer
127 votes
Answer Key / Explanation : (b) -
 (b) Till time  friction on car will be in forward direction and on boat in backward direction. So the boat will not move till . Let  be the velocity of car +boat system just after applying the brakes. From conservation of momentum, Time taken is
127 votes

127