Question

calculate the work done by the gravity when a child falls from the top of the 6m high wall

Answer 1

Gravitational force is all pervading force that is acting! Let’s assume that a particle is falling, the particle points in the direction of gravity. Its magnitude depends on how much is the mass (m), gravitational constant (g) and from what height it is falling (h)!

The Work done by gravity formula is given by,Wg = -mg(Δ h).


m is the mass,g is the gravity,h is height

The negative sign indicates that the particle is falling from a height ΔΔ h vertically in the direction of gravity. 

If θ is the angle it makes when the body falls. The work done by gravity is, W = mgh cos θ.Where, theta is the angle it makes when body falls.

Calculations 

Given: Height (h) = 6 m, 

The work done by gravity is given by,

W = -mgh cos θW = -6 m × 9.8 m/s × 12 m cos 23 ∘∘W = -(-705.6) J.
Therefore, the work done by gravity is -(-705.6) J.