Energy transfers - worksheet, Exams of Physics

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Combined science - Physics - Key stage 4 - Energy

Energy transfers - worksheet

Dr Fishwick

Exam style question

1. A car has a energy in its kinetic store as it is moving at 20 m/s. The driver applies the brakes and brings the car to a stop.

Describe the energy transfers that take place. 2

Q1.

Energy is transferred from the kinetic store of the car to the thermal store 1

by mechanical working 1

Match the store to the description

Store Description Chemical an object where the height has changed. Elastic potential an object that is moving. Electric-magnetic the state or temperature of an object. Gravitational potential an object moving back and forth. Kinetic objects that are being stretched or compressed. Nuclear energy stored in the molecules of an object. Thermal stored within the nuclei of atoms. Vibrational stored between charges or magnets being separated.

Independent practice

Identify the stores and pathways involved in the following examples

1. Describing a ball being dropped: Before we let go the ball has a gravitational store of energy. As the force of gravity does mechanical work on the ball making it fall, the gravitational store empties and the kinetic store increases. When it hits the ground, the thermal store of the surroundings increases by heating and the kinetic store of the ball decreases.

2. Describing a mass being lifted by a battery powered motor Before being turned on, the battery has a filled chemical store. When turned on, the chemical store is decreased by electrical working to turn the motor. This causes the mass to raise by mechanical work and increase its gravitational store.

Independent practice

Describe the stores and

transfers for each. Represent

the changes in a chart

1. A candle is lit, and burned

before being blown out.

2. A bungee jumper

jumping from a height

and stopping at the

bottom of the jump

chemical^ Thermal chemical^ Thermal chemical^ Thermal

Exam question practice

Answers

Review

1. What are the 8 stores of energy?
   • Electric-magnetic, kinetic, thermal, vibrational, elastic potential, gravitational potential, chemical, nuclear
2. What are the 4 pathways for transferring energy?

• Radiation, heating, mechanical, electrical

3. Which of the 4 pathways involves a force doing work on an object?

• mechanical

4. Which of the 4 pathways can involve light shining on an object?

• radiation

Review

Identify the stores and pathways involved in the following examples

1. Describing a ball being dropped: Before we let go the ball has a gravitational store of energy. As the force of gravity does mechanical work on the ball making it fall, the gravitational store empties and the kinetic store increases. When it hits the ground, the thermal store of the surroundings increases by heating and the kinetic store of the ball decreases.

2. Describing a mass being lifted by a battery powered motor Before being turned on the battery has a filled chemical store. When turned on the chemical store is decreased, by electrical working to turn the motor. This causes the mass to raise by mechanical work and increase its gravitational store.

Review

1. Energy is initially stored in the gravitational store of the person. It is

then transferred by mechanical working as the student falls to

eventually filling the elastic store of the rope.

Elastic

Stores pathways

GPE^ Elastic^ GPE

A question from Exampro

Review

The energy is initially stored in the elastic potential store of the spring. When this is released it does mechanical work and causes the car to move, increasing its kinetic store. As the car moves up the hill mechanical work is done against gravity to transfer this energy to the gravitational store of the car. When it has stopped all the energy is now stored in the gravitational store of the car.

Stores pathways

Elastic^ KE^ GPE Elastic KE GPE Elastic^ KE GPE