Question

A bicycle that weighs 10 kg is rolled up a hill that is 3.5m in height. What is the potential energy of the bike at the top of the hill? Same bike, however, the bike is now rolling down the hill at a velocity of about 2.5 m/s. What is the kinetic energy of the bike? Where would the potential energy of the bike be the lowest/minimum? Explain your logic.

Answer 1

Given that the mass of the bicycle is m = 10 kg

The height of the hill is h = 3.5 m

The velocity of the bicycle is v =2.5 m/s

We have to find potential energy and kinetic energy.

The potential energy can be calculated by the formula,

`P\mathrm{}E\text{. =mgh}`

Here, g = 9.81 m/s^2 is the acceleration due to gravity.

Substituting the values. the potential energy will be

`\begin{gathered} P\mathrm{}E\text{. = 10}*9.81*3.5 \\ =343.35\text{ J} \end{gathered}`

The kinetic energy can be calculated by the formula,

`\begin{gathered} K\mathrm{}E\text{. = }(1)/(2)mv^2 \\ =(1)/(2)*10*(2.5)^2 \\ =31.25\text{ J} \end{gathered}`

The potential energy will be minimum when it reaches the ground as height is minimum.