Question

An outfielder throws a 1.1 kg baseball at a speed of 62 m/s and an initial angle of 12.3 ◦ . What is the kinetic energy of the ball at the highest point of its motion? Answer in units of J.

Answer 1

Answer:

= 2,018.3 J

Explanation:

mass (m) = 1.1 kg

velocity (v) = 62 m/s

initial angle(θ) = 12.3°

kinetic energy = $0.5mv^{2}$

where

• m is the mass
• v is the velocity, which has two components

      v = Vx + Vy  (horizontal component + vertical component)

      at the maximum height, velocity is 0, so Vy = 0 and v= Vx

      v = Vx = v.cosθ

      v = 62 x cos 12.3 = 60.6 m/s

therefore kinetic energy = $0.5mv^{2}$ = $0.5x1.1x60.6^{2}$

= 2,018.3 J