Question

A ball is thrown up with an initial velocity of 20 m/s and after some time it returns. What is the maximum height reached? Take g = 10 m/s^2.

(a) 80m

(b) 20m

(c) 70m

(d) 40m

I have been asked this question by my college professor while I was bunking the class.

Enquiry is from Kinematic Equations for Uniformly Accelerated Motion in section Motion in a Straight Line of Physics – Class 11

Answer 1

Correct answer is (b) 20m

Best explanation: Here we will use the third equation of motion. The third equation of motion is v^2 = u^2 + 2as. At the maximum height, the velocity of the ball will be zero, therefore, v = 0, u = 20, and a = -g = -10. On solving, we will get s = 20m.