energy conservation

Multiple Choice

As a roller coaster moves down a steep hill, its Potential Energy is converted into Kinetic Energy, Thermal Energy and Sound Energy. Which of the following statements is TRUE about the total energy of this system?

• Energy is gained (created) as the roller coaster moves faster.

• Energy is lost (destroyed) as the roller coaster moves faster.

• The total energy remains the same as the roller coaster moves faster.

• The total energy is constantly changing as the roller coaster moves faster.

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Multiple Select

Which changes will INCREASE the energy in a system?

• When MORE energy ENTERS than exits

• When LESS energy ENTERS than exits

• When MORE energy EXITS than enters

• When LESS energy EXITS than enters

Multiple Choice

A pendulum swings from its highest point to its lowest point. If its speed at the lowest point is 4 m/s and its mass is 2 kg, what is its kinetic energy at the lowest point?

• 8 J

• 16 J

• 32 J

• 64 J

Multiple Choice

When is kinetic energy transferred from object to object?

• when those objects pass one another

• when the first object outweighs (weights more than) the second object

• when the first object has more potential energy than the second object

• when those objects collide

Multiple Choice

What type of energy is transferred from the kinetic store of the bat to the kinetic store of the ball?

• Kinetic energy

• Thermal energy

• Potential energy

• Chemical energy

Multiple Choice

What is the principle demonstrated by the example of boiling water in a kettle?

• Conservation of energy

• Energy dissipation

• Thermal expansion

• Electrical resistance

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Multiple Choice

What do the different parts of a Sankey diagram represent?

• Energy transferred into the system

• Wasted energy

• Useful energy output

• Total energy in

Multiple Choice

What does the width of each arrow in a Sankey diagram represent?

• The amount of energy being transferred

• The total energy in

• The wasted energy

• The useful energy out

Multiple Choice

What is the difference in energy transferred by radiation between a modern energy efficient light bulb and an old filament light bulb?

• 75 J

• 10 J

• 90 J

• 25 J

Multiple Select

look at the last two questions Suggest why modern bulbs are more efficient? (There is more than one correct answer)

• They do not need as big an energy input

• They are not as bright

• There is less wasted energy

• They release less heat.

Multiple Choice

The illustration shows a lamp plugged into an outlet.
When the lamp is turned on and the bulb is lit, the circuit demonstrates which of the following?

• Sound energy changing to light energy
• Electrical energy changing to light energy
• Electrical energy producing mechanical energy
• Light energy producing sound and heat energy

Open Ended

Calculate the amount of wasted energy.

Multiple Choice

What is the definition of efficiency in the context of energy transfer?

• The measure of energy wasted

• The ratio of useful energy output to total energy input

• The total energy consumed by a system

• The amount of energy produced by a system

Multiple Choice

If a device uses 1000 J of energy but only 200 J is used for useful work, what is the efficiency of the device?

• 5%

• 20%

• 80%

• 95%

Multiple Choice

A crane lifts an 8-m long steel girder weighing 2600 N up 15 m off the ground. The crane did ___ of work.

• 0 J

• 39000 J

• 20800 J

• 2600 J

Multiple Choice

An Olympic high jumper, with a mass of 82 kg, has a maximum gravitational potential energy of 1970 J. How high was the jump?

Let g = 9.8N/kg

• 24 m

• 161,540 m

• 2.5 m

• 201 m

Multiple Choice

What is the formula for calculating power input based on power output and efficiency?

• power input = power output / efficiency

• power input = efficiency / power output

• power input = power output + efficiency

• power input = power output - efficiency

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Multiple Choice

What is the energy conversion when you put batteries in a flashlight to make it turn on?

• chemical to light

• light to motion

• chemical to thermal

• nuclear to light

Poll

How confident do you feel about this topic now?

• Very confident
• Somewhat confident
• Not confident