Question

A baseball of mass 1.23 kg is thrown at a speed of 65.8 mi/h. What is its kinetic energy?

Answer 1

Given:

The mass of the ball is

`m=1.23\text{ kg}`

The speed of the ball is

`\begin{gathered} v=65.8\text{ mi/h} \\ \end{gathered}`

Required: calculate the kinetic energy of the baseball

Step-by-step explanation: to calculate the kinetic energy of a body we will use the formula as

`K.E=(1)/(2)mv^2`

first, we convert velocity from mi/h into m/s.

we know that

`1\text{ mi=1609.34 m}`

and

`1\text{ h=3600 sec}`

then the velocity is

`\begin{gathered} v=\frac{65.8*1602.34\text{ m}}{3600\text{ s}} \\ v=29.29\text{ m/s} \end{gathered}`

now plugging all the values in the above formula, we get

`\begin{gathered} K.E=(1)/(2)mv^2 \\ K.E=(1)/(2)*1.23\text{ kg}*(29.29\text{ m/s})^2 \\ K.E=527.61\text{ J} \end{gathered}`

Thus, the kinetic energy of the baseball is

`527.61\text{ J}`