A ball weighing 100 g rolls on the floor at a speed of 0.2 m / s. What is its kinetic energy.

1. Let’s write down the condition of the problem:

m = 100 g

V = 0.2 m / s

E kin. -?

2. Let’s translate all units of measurement into the SI system:

m = 100 g = 0.1 kg

V = 0.2 m / s

E kin. -?

3. Let’s write down the standard formula for calculating the kinetic energy:

E kin. = m × V ^ 2/2

4. Substitute the numerical values from the condition into the formula and calculate the final answer:

E kin. = 0.1 kg × 0.2 m / s ^ 2/2 = 0.1 × 0.04 / 2 = 0.004 / 2 = 0.002 J

5. Let’s translate the resulting number into more convenient units of measurement and write down the answer:

0.002 J = 2 mJ

Answer: 2 mJ