A 34.8 kg runner has a kinetic energy of 1.09 x 10³ J. What is the speed of the runner?

7.91 m/s

Explanation:

Speed: This can be defined as the ratio of this to time. Speed can also be the magnitude of a velocity or speed is velocity without direction.

The S.I unit of speed is m/s.

From the question,

K.E = 1/2(mv²) Equation 1

Where K.E = Kinetic Energy, m = mass of the runner, v = velocity of the runner.

make  v the subject of the equation

v = √(2K.E/m)Equation 2

Given: K.E = 1.09×10³ J, m = 34.8 kg.

Substitute into equation 2

v = √(2× 1.09×10³/34.8)

v = √(62.64)

v = 7.91 m/s.

Hence the speed of the runner = 7.91 m/s

no. dot product   =0 when vecs at right angles