Answer :

Answer: 10 m/s

Explanation:

The formula for kinetic energy is:

K = (1/2)mv², where:

  • K is the kinetic energy of the object (J)
  • m is the mass of the object (kg)
  • v is the velocity of the object (m/s)

We are given:

  • K = 20 J
  • m = 400g = 0.4 kg

Let's substitute these values into the formula:

20 = (1/2)(0.4)v²

Solve for v:

40 = 0.4v²

100 = v²

v = √100

v = 10 m/s

The velocity of the ball is 10 m/s.