Gravitational Potential Energy Flashcards

All 6 cards in this deck

What is the equation for the change in gravitational potential energy of an object raised above the ground?

$\Delta GPE = m \times g \times \Delta h$ (change in GPE in J = mass in kg × gravitational field strength in N/kg × change in vertical height in m)

What value of gravitational field strength $g$ is used for the Earth in GCSE energy calculations, and what are its units?

$10$ N/kg (a value of $9.8$ N/kg is also accepted).

What are the steps to calculate the change in gravitational potential energy?

e.g. a $2$ kg book is lifted $3$ m, $g = 10$ N/kg

1. Write the equation: $\Delta GPE = m \times g \times \Delta h$
2. Substitute: $2 \times 10 \times 3$
3. Evaluate: $60$ J

What are the steps to find the height an object must fall to gain a given amount of energy?

e.g. $6$ kg of water gains $300$ J, $g = 10$ N/kg

1. Write the equation: $\Delta GPE = m \times g \times \Delta h$
2. Rearrange: $\Delta h = \dfrac{\Delta GPE}{m \times g} = \dfrac{300}{6 \times 10}$
3. Evaluate: $5$ m

True or false? The change in gravitational potential energy of an object pushed up a ramp depends on the distance travelled along the ramp.

False. It depends only on the change in vertical height.

What must you do with a mass given in grams before using it in an energy equation?

e.g. $500$ g

Convert it to kilograms by dividing by $1000$: $500$ g $= 0.5$ kg.