An object with a mass of $18 k g$ $18 kg$ is hanging from an axle with a radius of $12 c m$ $12 cm$ . If the wheel attached to the axle has a radius of $28 c m$ $28 cm$ , how much force must be applied to the wheel to keep the object from falling?

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Answer 1 · 2016-04-16T15:47:55

$75.6 N$ $75.6 N$

While the body is not falling, total torques applied on the centre of the axle by the weight of the object and the force applied should be zero.

And as torque $τ$ $tau$ is given as $τ = F \cdot r$ $tau = F*r$ , we can write:

$Weight \cdot 12 c m = Force \cdot 28 c m$ $"Weight" * 12 cm = "Force"* 28cm$

$Force = \frac{18 \cdot 9.8 \cdot 12}{28} N = 75.6 N$ $"Force"= (18*9.8*12)/28 N = 75.6 N$

An object with a mass of 18 kg18kg18 kg is hanging from an axle with a radius of 12 cm12cm12 cm. If the wheel attached to the axle has a radius of 28 cm28cm28 cm, how much force must be applied to the wheel to keep the object from falling?