Question

A child riding a bike at a speed of 0.6m/s with a total kinetic energy of 12.4j. If the mass of the child is 30kg, how do I calculate the mass of the bike?

Answer 1

Answer:

K.E = 1/2 m1v^2

K.E = 1/2 (M+m)v^2

12.4 = 1/2 (30 + m) x 0.6 x 0.6

24.8/0.36 = 30 + m

2480/36 = 30 + m

m = 38.9 kg

Answer 2

Mass of child = 30kg

Kinetic energy = 12.4J

Velocity = 0.6m/s

Let mass of bike be m

Total mass of child and bike = (m+30)

Kinetic energy = 1/2 mv²

Kinetic energy = 1/2 (m+30) (0.6)²

12.4 = 1/2 (m+30) 0.36

12.4 × 2 = (m+30) 0.36

24.8 = 0.36m + 10.8

24.8 - 10.8 = 0.36m

14/0.36 = m

1400/36 = m

38.8 kg = m

Therefore mass of bike is 38.8kg