Question

A body of mass 2 kg is thrown vertically upwards with an initial velocity of 20 m/s. What will be its the potential energy at the end of 2 sec ?

• A. $300J$
• B. $400J$
• C. $10J$
• D. $40J$

Answer 1

The correct option is B $400J$

From equation of motion, $h=ut+\frac{1}{2}a{t}^2$

$h=20\times 2-\frac{1}{2}\times 10\times 2\times 2$

$h=40m-20m$

$h=20m$

Now,

Potential Energy, $PE=mgh$

$PE=2\times 10\times 20J$

$PE=400J$