Conservation of Energy and Efficiency

What force causes a roller coaster cart to slow down the most?

• friction

• weight

• gravity

• air resistance

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NGSS.MS-PS2-2

NGSS.MS-PS3-5

What energy transformation occurs from a light bulb? 

• Electrical energy = kinetic energy + potential energy 
• Electrical energy = electrical energy 
• Electrical energy = chemical energy 
• Electrical energy = light energy + thermal energy 

The law of energy conservation says the total energy before the change _______ the total energy after it

• is less than
• is more than
• affects
• equals

Tags

NGSS.MS-PS3-5

Roller coasters slow down because their energy disappears.  

• True 
• False

Tags

NGSS.MS-PS3-5

What happens when the ball goes from the highest position to the lowest position

• PE and KE increases and decreases together

• Impossible to know without knowing the mass of the object

• the PE decreases while KE increases

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-5

A toy car down a ramp loses most of its energy to

• thermal

• sound

• heat

• gravity

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Total energy = 200J Useful energy = 20J Workout the efficiency of this lightbulb.  

• 100%

• 80%

• 40%

• 10%

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NGSS.MS-PS3-3

Total energy = 350J Useful energy = 70J Workout the efficiency of this iphoneX.  

• 100%

• 80%

• 40%

• 20%

Tags

NGSS.HS-PS3-1

This car needs 8600J of energy to power it. If 5000J is changed into useful energy, how much energy is wasted?

• 13600J

• 3600J

• 5000J

• 8600J

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NGSS.MS-PS3-4

NGSS.MS-PS3-5

A car transfers 100 J of chemical energy in order to gain 50 J of kinetic energy. The efficiency of the car is

• 20%

• 0.5%

• 50%

• 200%

Tags

NGSS.MS-PS3-5