Question

A golf pro has 2100 J of kinetic energy and swings his driver which weighs .75 kg. What is the speed of his swing?

Answer 1

The speed of his swing is 56 m/s

Answer 2

Answer : The correct answer is 74.83 m/s .

The kinetic energy is energy possessed by any mass which is moving or have some speed . It is product of mass and velocity . It is expressed as :

`KE = (1)/(2) * m* v^2`

Where KE = kinetic energy in J or
`kg(m^2)/(s^2)` m = mass in Kg v = speed in m/s²

Unit of KE is Joules (J) .

Givne : KE = 2100 J mass = 0.75 kg v = ?

Plugging value in KE formula =>

`2100 J = (1)/(2) * 0.75 Kg * v^2`

`2100 J = 0.375 Kg * v^2`

Dividing both side by 0.375 kg =>

`(2100 J)/(0.375 Kg) = (0.375 Kg)/(0.375 Kg ) * v^2`

`v^2 = 5600 (m^2)/(s^2)`

`v= 74.83 (m)/(s)`