Question

a body of mass 3kg is thrown vertically upwards with an initial velocity 20m/s what will be its potential energy at the end of 2s (take g equal 10m/s2

Answer 1

Answer:

600J

Explanation: h=ut+1/2gt^2

                      h=20x2+1/2x-10x2x2

                      h=20m

E=mgh

E=3x10x20

E=600J

Answer 2

Given,

1. Mass of the body(m)= 3 kg
2. Initial velocity of the body when thrown upwards(u) = 20ms⁻¹
3. Time(t) = 2 s
4. Gravitational Force(g) = 10ms⁻²

To Find,

The potential energy of the body at the end of the given time.

Solution,

We will first have to find the height reached by the body in the given time.

The formula for the height

Height(h) = ut - $\frac{1}{2}$gt²

= (20 × 2) - $\frac{1}{2}$ × 10 × 2²  

= 40 - 20 = 20 m

Now we can find the potential energy of the body.

Potential Energy(P) = mgh =2 × 10 × 20 = 400 J

Hence, the potential energy of the body after 2 seconds will be 400 J.