Question

The mass of a bike and cyclist is 75.0 kg. The rider starts at rest at a height of Om. She speeds up to 6.00 m/s. What is the mechanical energy of thebike?The answers would be one of the four choices in the pictures.

Answer 1

Given that the mass of the bike and cyclist is m = 75 kg and the velocity is v = 6 m/s. The height is h= 0 m

Mechanical energy is the sum of kinetic energy and potential energy.

The kinetic energy is given by the formula

`\begin{gathered} K.E\text{. =}(1)/(2)mv^2 \\ =(1)/(2)*75*(6)^2 \\ =1350\text{ J} \end{gathered}`

The potential energy is given by the formula,

`\begin{gathered} P\mathrm{}E\mathrm{}=\text{mgh} \\ =75*9.8*0 \\ =0\text{ J} \end{gathered}`

Here, g = 9.8 m/s^2 and is the acceleration due to gravity.

The mechanical energy will be

`\begin{gathered} E=\text{ 1350 J+0 J} \\ =1350\text{ J} \end{gathered}`