Question

The potential energy of a catapult was completely converted into kinetic energy by releasing a small stone with a mass of 20 grams. The velocity of the stone when it reached the target was 15.0 meters/second. What was the value of the kinetic energy of the stone when it reached the target?

Answer 1

1,000 grams = 1 kilogram
20 grams = 0.02 kilogram

Kinetic energy = (1/2) (mass) x (speed)²

(1/2) (0.02) x (15)² =

(0.01) x (225) = 2.25 joules

Answer 2

Answer: 2.25 J

Step-by-step explanation: Kinetic energy is the energy possessed by an object by virtue of its motion.

`K.E=(1)/(2)* mv^2`

m= mass of object= 20 g = 0.02 kg (1 kg= 1000 g)

v= velocity of object= 15 m/s

`K.E=(1)/(2)* 0.02* 15^2=2.25kgm^2s^(-2)=2.25J`

`(1J=1kgm^2s^(-2))`