Use Coupon: CART20 and get 20% off on all online Study Material

Total Price: Rs.

There are no items in this cart.
Continue Shopping
Grade: 12


The figure shows two boats A and B with B connected by a string on the surface of a lake. A person in boat A pulls the string by a constant force of 50N. The combined mass of boat A and the person in it is equals to 250 kg and that of boat B is 500 kg. Show that the velocity of boat A relative to the boat B , 5 sec after the person in the first boat begins to pull the rope is 1.5 m/s.

10 years ago

Answers : (1)

askIITianexpert IITDelhi
8 Points

Considering both boats A & B as a system will render pull of the person as an internal force for the system.

So their "Center of Mass" will not shift.Taking it as origin,

                                                             -MaXa + MbXb = 0  where  Ma & Mb are respectively 250kg. & 500kg.

                                                                                               Xa=distance of boat A from origin(Center of Mass of the system here)

                                                                                               Xb=distance of boat B from origin in (+ve) X-direction.

                                     or,            MbXb = MaXa

                                        Differentiating w.r.t time 't' twice,

                                                            MbΔb = MaΔa               where  Δa & Δb are respectively accelerations towards each other.

      Hence relative acceleration Δab = Δb + Δa = [ (Ma+ Mb)/Ma]*Δb = 3Δb = 3*(50N/500kg)=0.3 mtrs./sec.2

                                            Vab=ab)*(5sec.)=1.5 m/s

10 years ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies

Course Features

  • 101 Video Lectures
  • Revision Notes
  • Previous Year Papers
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Test paper with Video Solution

Course Features

  • 110 Video Lectures
  • Revision Notes
  • Test paper with Video Solution
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Previous Year Exam Questions

Ask Experts

Have any Question? Ask Experts

Post Question

Answer ‘n’ Earn
Attractive Gift
To Win!!! Click Here for details