A 10 kg block is pulled in the vertical plane along a frictionless surface in the form of an arc of a circle of radius 10m. The applied force is 200N as shown in the figure. If the block started from rest at A, the velocity at B would be:

Options

A. `sqrt(3) m//s`
B. `10sqrt(3) m//s`
C. `100sqrt(3) m//s`
D. None of these

Answer

B

Explanation

System is block and string. Applying work energy theoram on system
`(200)10-10g(R-R cos 60^(@)) =1/2 (10)v^(2)`
`2(200-10xx5) =v^(2)`
`v=sqrt(300)=10sqrt(3) m//s`