Question

A body of mass 1 kg is released from a height of 5 m calculate the potential energy and kinetic energy when it is at height of 2 m from the ground. ( g :9.8 )

Answer 1

Answer:

Potential energy is 29.4 J and kinetic energy is 29.4 J

Explanation:

Mass of body m =1 kg

Intitial height h1 =5m

Final hieght h2 =2m

Distance travelled S= 5-2 =3m

From the equation of motion we can find the final velocity as initially it body at rest .

$v^2=u^2+2aS\\v^2=u^2+2gS\\v^2=0+2\times 9.8\times 3\\V^2=58.8 \\v=\sqrt{58.5} \\v=7.668 m/s$

Potential energy of the body is

$PE= mgh =mgS\\=1\times 9.8 \times 3\\=29.4 J$

Kinetic energy is

$KE=\frac{1}{2} mv^2\\KE=\frac{1}{2} \times 1 \times 7.668^2\\KE=29.4 J$

Potential energy is 29.4 J and kinetic energy is 29.4 J