Question

A rope of length $10 \, m$ and linear density $0.5 \, kg \, m^{- 1} \, $ is lying length wise on a smooth horizontal floor. It is pulled by a force of $25 \, N$ . The tension in the rope at a point $6 \, m$ away from the point of application is

• A. 20 N
• B. 15 N
• C. 10 N
• D. 5 N

Answer 1

Answer: (C)

Mass of rope $=10\times 0.5=5 \, kg$
Given force $=25 \, N$
Acceleration $=\frac{F}{m}=\frac{25}{5}=5 \, ms^{- 2}$
Length of remaining rope $=4m$
Hence mass of remaining rope $=4\times 0.5=2kg$
Hence tension on the rope at a point 6m away $=m\times a=2\times 5=10N$