Question

A uniform beam is balanced at its mid-point an object placed on the beam as shown.

 

Which force will rebalance the beam?

Options

• 30 N (upward), 60 cm to the left of the mid-point.

• 30 N (upward), 60 cm to the right of the mid-point.

• 45 N (downward), 45 cm to the right of the mid-point.

• 90 N (downward), 20 cm 10 to the left to mid-point

Answer 1

30 N (upward), 60 cm to the left of the mid-point.

Explanation:

The 60 N force works as an anti-clockwise moment of (60 × 30) N-cm in this case, which can be balanced by a clockwise moment of (60 × 30) N-cm. So, among the possibilities shown, a 30 N force operating upwardly at 60 cm to the left of the mid-point can balance the supplied moment.