Question

A roller of mass $300kg$ and of radius $50cm$ lying on horizontal floor is resting against a step of height $20cm$. The minimum horizontal force to be applied on the roller passing through its centre to turn the roller on to the step is :

• A. $980N$
• B. $1960N$
• C. $2940N$
• D. $3920N$

Answer 1

The correct option is D $3920N$

Balancing torque about the highest point of the step ( corner point )

$F_{min}\times 30=40mg$

$\Rightarrow F_{min}=\frac{40\times 300\times 9.8}{30}=3920N$