Question

A car has a kinetic energy of 103kJ. The speed of the car is 13. 1 m/s. Calculate the mass of the car. Give your answer to 2 significant figures

Answer 1

`\huge{ \boxed{ \boxed{1200 \: kg}}}`

Step-by-step explanation:

The formula for kinetic energy is given as;

`k = (1)/(2) m {v}^(2) \\`

where

m is the mass in kg

v is the velocity in m/s

k is the kinetic energy in J

Making mass the subject we have

`m = \frac{2k}{ {v}^(2) } \\`

From the question

k = 103 kJ = 103,000 J

v = 13.1 m/s

`m = \frac{2 * 103000}{ {13.1}^(2) } = (206000)/(171.61) \\ = 1200.396 \approx \: 1200`

We have the final answer as

1200 kg