Draw an energy flow diagram for the following power transmission system:

• Solar panel ($20\%$ efficient)
• Solar inverter (converts DC to AC, $95\%$ efficient)
• Step-up transformer ($95\%$ efficient)
• Overhead power transmission cable ($95\%$ efficient)
• Step-down transformer $95\%$ efficient).

Assume that there is $1000 \mathrm{J}$ of solar energy arriving at the solar panel.

Draw an energy flow diagram for the following power transmission system:

• Solar panel ($20\%$ efficient)
• Solar inverter (converts DC to AC, $95\%$ efficient)
• Step-up transformer ($95\%$ efficient)
• Overhead power transmission cable ($95\%$ efficient)
• Step-down transformer $95\%$ efficient).

Assume that there is $1000 \mathrm{J}$ of solar energy arriving at the solar panel.

What is the overall efficiency of the power transmission system?

State the equations for kinetic energy with mass as the subject.

$k.e: m=\_\_\_\_\_\_\_$

State the equation for change in gravitational potential energy, with mass as the subject.
$\mathrm{Change} \mathrm{in} \mathrm{gravitational} \mathrm{potential} \mathrm{energy}\times \mathrm{mass}=\_\_\_\_\_\_\_$ 

Calculate the kinetic energy of a car of mass $600 \mathrm{kg}$ travelling at $25 \mathrm{m} {\mathrm{s}}^{-1}$.

A walker carrying a $20 \mathrm{kg}$ back pack climbs to the top of a mountain $2500 \mathrm{m}$ high. Calculate the gain in gravitational potential energy of the pack.
(Acceleration due to gravity $g=10 \mathrm{m} {\mathrm{s}}^{-2}$).

The car of mass $600 \mathrm{kg}$ is travelling at $25 \mathrm{m} {\mathrm{s}}^{-1}$ slows down to a speed of $12 \mathrm{m} {\mathrm{s}}^{-1}$. By how much has its kinetic energy decreased?

A girl throws a ball upwards as shown in figure. The ball has a mass of $0.20 \mathrm{kg}$ and it leaves her hand with a speed of $8.0 \mathrm{m} {\mathrm{s}}^{-1}$. Determine how high it will rise.

In a game, a toy car, which is initially stationary, slides down a slope. The top of the slope is $2.0 \mathrm{m}$ higher than the foot of the slope. Determine how fast the car will be moving when it reaches the foot. (Assume that all of its gravitational potential energy is converted into kinetic energy). (Take $g=10 {\mathrm{ms}}^{-2}$).