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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?

Verified Answer :

AL2006


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: 2.25 J

Explanation: Kinetic energy is the energy possessed by an object by virtue of its motion.

\(K.E=\frac{1}{2}\times mv^2\)

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

v= velocity of object= 15 m/s

\(K.E=\frac{1}{2}\times 0.02\times 15^2=2.25kgm^2s^{-2}=2.25J\)

\((1J=1kgm^2s^{-2})\)

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