Question

10 kg ball is dropped from a height of 10 m. What is the speed of the ball just before it reaches the ground?

• A. 14 m/s
• B. 20 m/s
• C. 35 m/s
• D. 21 m/s

Answer 1

The correct option is A

14 m/s

At the height of 10 m, the potential energy = mgh

10 kg x 9.8 m/s² x 10 m = 980 J

Now, let the speed of the ball just before it reaches the ground be v

Then, kinetic energy = 1/2 x mv²

980 = 1/2 x 10 x v²

v = 14 m/s