Question

A boy and his dog are running. The dog has a mass of 20kg and the boy has a mass of 45kg.
Suppose both the dog and the boy run at a speed of 3m/s. Evaluate the expression for kinetic energy to find both of their kinetic energies:
KE of Boy:
KE of Dog:
Suppose the dog speeds up and is now running at a speed of 6m/s. Calculate the dog’s new KE.
New KE of Dog:
Pls answer quick! Thank you

Answer 1

Answer:

Explanation:

mass of boy =m1=45 kg

mass of dog =m2=20kg

the speed of boy=3 m/s

the speed of dog =3 m/s

K.E of boy  

K.E=1/2mv²

K.E=1/2(45)(3)²

K.E=202.5 J

K.E of dog

K.E=1/2mv²

K.E=1/2(20)(3)²

K.E=90 J

now the new speed of dog is 6 m/s

therefore new K.E of dog is

K.E=1/2(20)(6)²

K.E=360 j