Question

The question I need help with is number 13 and everything is on the imagine below

Answer 1

We are given that an object falls 10 meters. To determine the amount of kinetic energy we need to consider a balance of energy. Since the total energy is preserved this means that the kinetic energy that the object gains is equivalent to the gravitational energy of the object when it is 10 meters in height, therefore, we have:

`K=E_g`

Where:

`\begin{gathered} K=\text{ kinetic energy} \\ E_g=\text{ potential gravitational energy} \end{gathered}`

The gravitational energy is given by the following formula:

`E_g=\text{mgh}`

Where:

`\begin{gathered} m=\text{ mass} \\ g=\text{ acceleration of gravity} \\ h=\text{ height} \end{gathered}`

Since we are given the weight of the object and since the weight is the product of the mass and the acceleration of gravity the formula simplifies to:

`E_g=wh`

Where:

`w=\text{ weight}`

Now, we substitute the values in the formula:

`E_g=(20N)(10m)`

Solving the operations:

`E_g=200J`

Therefore, the gravitational energy is 200 Joule, since the kinetic energy is equal to the gravitational energy in this case, we have that the object gains 200 Joules of kinetic energy.