Question

A stone of mass 0.55 kilograms is released and falls to the ground. Measurements show that the stone has a kinetic energy of 9.8 joules at the point of impact with the ground. What is the stone's velocity when it hits the ground?
a.6.3 meters/seconds
b.7.2 meters/seconds
c.8.1 meters/seconds
d.9.3 meters/seconds

Answer 1

Answer:

The correct answer is option a.

Explanation:

Kinetic energy is the energy of the object due to its motion.

Mass of the stone = m = 0.55 kg

Velocity of the stone = v

Kinetic energy of the stone when it hits the ground = K.E = 9.8 Joules

Kinetic energy is given as:

$K.E=\frac{1}{2}mv^2$

$9.8 J=\frac{1}{2}\times 0.55 kg\times v^2$

$v^2=\frac{9.8 J\times 2}{0.55 kg}$

$v=5.96 m/s \approx 6 m/s$

6.3 m/s the stone's velocity when it hits the ground.

6.3 m/s ≈ 6 m/s

The closest option to our answer is option a.