Question

A key is 5 cm long and turns the levers of a lock at a 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 1

Key is a lever of second order.

Given: Load arm (d) = 1 cm

∴ Effort arm (D) = 5 cm

Effort (E) = 10 N, Load (L) = ?

Now, Load × load arm = Effort × effort arm

Load × 1 cm = 10 N × 5 cm

\[ \therefore\ \text{Load} = \frac{10\ \text{N} \times 5\ \text{cm}}{1\ \text{cm}} \]

= 50 N