Physics 5054 · O Level · Turning effect of forces

Turning effect of forces — practice question

Fig. 2.1 illustrates a bed that folds up against a wall in the daytime. In the horizontal position, it is held up on one side by a hinge and on the other side by two legs. The weight $W$ of the bed acts through its centre of mass, which is $0.35\,\text{m}$ horizontally from the hinge.
(a)[1]

The bed has a mass of $26\,\text{kg}$. The gravitational field strength is $10\,\text{N kg}^{-1}$. Calculate the weight $W$ of the bed.

(b(i))[2]

State the principle of moments

(b(ii))[3]

Find the magnitude of the total upward force applied to the bed by the two legs when the bed is horizontal.

Worked solution & mark scheme

This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: 260\,\text{N}

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