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

The correct answer is option a.

Step-by-step 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=(1)/(2)mv^2`

`9.8 J=(1)/(2)* 0.55 kg* v^2`

`v^2=(9.8 J* 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.