Question

Which has more kenetic energy: A 150 g bullet fired from a gun achieving a velocity of 440 m/s and a standard baseball weighing 51/4 oz being pitched at he MLB record speed of 105.1 mph. Calculate kinetic energy in Joules.

Answer 1

Answer:

Bullet has more kinetic energy then baseball.

Explanation:

Mass of the bullet , m = 150 g = 0.150 kg

Velocity of the bullet = v = 440 m/s

Kinetic energy =$\frac{1}{2}\times mass\times (velocity)^2$

Kinetic energy of the bullet = K.E

$K.E=\frac{1}{2}mv^2=\frac{1}{2}\times 0.150 kg\times (440 m/s)^2$

$=14,520 Joules$

Mass of the baseball, m' = $\frac{51}{4} oz$= 0.36146 kg

(1 ounce = 0.0283495 kg)

Velocity of the baseball= v' = 105.1 mph

1 mile = 1609.34 m

1 hour = 3600 seconds

$v'=\frac{ 105.1\times 1609.34 m}{3600 s}=46.98 m/s$

Kinetic energy of the baseball = K.E'

$K.E'=\frac{1}{2}m'v'^2=\frac{1}{2}\times 0.36146 kg\times (46.98 m/s)^2$

$=398.83 Joules$

14,520 Joules > 398.83 Joules

K.E > K.E'

Bullet has more kinetic energy then baseball.