Question 28

A body of mass 2 kg is thrown upward with initial velocity of 20 m/s. After 2 seconds,its kinetic energy will be: $$(g=10\frac{m}{s^2})$$

Solution

We know that, Kinetic energy is

K.E. = $$\frac{1}{2}mv^2$$

$$V=u+at$$

$$u=20ms^{-1}$$

$$t=2\sec onds$$

$$a=-10ms^{-2}$$

Because, here body is going upward so we will take acceleration as negative.

$$v=20+2\left(-10\right)=20-20=0$$

K.E. = $$\frac{1}{2}mv^2$$

Hence K.E.= 0

Option A is right answer.

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