Question

A ball is thrown upward at a speed of 28 meter per second. What is the speed of ball one second before reaching maximum height? (Given that g= 10 meter per second²)

Options

• 10 meter per second

• 1 meter per second

• 2 meter per second

• 18 meter per second

Answer 1

10 meter per second

Explanation:

At maximum height

V = 0, u = 28 m/s, g = – 10 m/s and t = ?

∴ V = u + gt

⇒ 0 = 28 – 10t

⇒ t = 2.8 sec.

At one second before reaching maximum height.

u = 28 m/s, g = – 10 m/s and t = 2.8 – 1 = 1.8 sec.

∴ v = u + g t

v = 28 – 10 × 1.8 = 10 m/s