Question

A key is 5 cm long and turns a levers of the lock at the distance of 1 cm. If the lock is opened by an effort of 10 N, calculate the resistance offered by the levers of the lock.Answer with complete procedure. Quick!!!!

Answer 1

Force applied by you = 10N
length of key = 5cm
so force arm for you = 5cm

let resistance offered by levers of key = F
distance of levers = 1cm
so force arm for lever = 1cm

Balancing the moments,
10N × 5cm = F × 1cm
⇒ F = 50N

So resistance offered by the levers of the lock is 50N.

Answer 2

Let the force be F .

By principal of moment of forces :

Sum of anticlockwise moments = Sum of clockwise moments .

Hence : 10 N × 5 cm = 1 cm × F

⇒ F cm = 50 N cm

⇒ F = 50 N

ANSWER :

The force is 50 N