Question

A door $1.6m$ wide requires a force of $1N$ to be applied at the free end to open or close it. The force that is required to be applied at a point $0.4m$ distant from the hinges for opening or closing the door is

• A. $1.2N$
• B. $3.6N$
• C. $2.4N$
• D. $4N$

Answer 1

The correct option is D $4N$

$\tau =1.6Nm\tau =F\times 0.41.6=F\times 0.4\therefore F=4N$