Question

A $10kg$ 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 of constant magnitude $200N$ as shown in the figure. If the block started from rest at $A$, its speed at $\theta$ would be

• A. $1.732m/s$
• B. $17.32m/s$
• C. $2m/s$
• D. $20m/s$

Answer 1

The correct option is B $17.32m/s$

Ref. image 1

Work done by force = F.d

$\Rightarrow w=200N\times 10m=2000J$

Ref. image 2

$[R\sin 30=\frac{d}{2}]$

$\Rightarrow R=d$

$\Rightarrow d=10m$