Question

A ball of mass 200g falls from a height of 5m. What is its Kinetic Energy when it just reaches the ground?

• A. 9.8 J
• B. 98 J
• C. 980 J
• D. none of these

Answer 1

The correct option is A 9.8 J

All the forces acting are conservative so mechanical emergy will be conserved for the body .

Taking ground surgace as refrence point its initial potential energy is mgh =9.8J. (converting all perameters in SI units)

And final potential energy is zero as h=0.

Also its initial kinetic energy is zero.

Now applyning law of conservation of energy we get final kinetic energy is 9.8J