Energy Summative

The law of the conservation of energy states...

• Energy can be destroyed only if it is transformed and transferred. 
• Energy can never be created or destroyed it only transfers and transforms from one system to another.
• Energy can only be transferred, never transformed, and can't be created.
• Energy is only destroyed, never created, and only transforms.

What would cause the newton cradle to stop swinging?

• The energy is destroyed on impact when a newton ball strikes another newton ball.
• Energy is created during this process and the newton cradle will actually swing forever.
• The energy transformation ultimately destroys the energy.
• The newton cradle will stop swinging when the energy of the system has transformed into thermal and sound energy (dissipated).

What role does friction play in the world of energy? 

• Friction destroys kinetic energy.
• Friction creates kinetic energy.
• Friction transforms kinetic energy to thermal energy.
• Friction creates new energy by destroying a previous energy.

If the weight is dropped onto the tent stakes, will all of the 20 units of gravitational potential energy transfer to the tent stake on impact? 

• Yes, 100% of the energy will transfer because it can't be destroyed.
• No, some of the energy will transform into sound and thermal, less than 20 units will transfer to the stake.
• Yes, 100% of the energy will transfer because energy is being created.
• No, 100 % of the energy will dissipate before impact.

What does it mean if energy is dissipated? 

• It means the energy of a system was transformed into thermal and sound energy and likely transferred to another system.
• It means energy was destroyed from a system.
• It means energy was created from one system and passed to another.
• It means energy was destroyed from one system and passed along to another system.

What would happen to the person swinging if the friction of the swing increased?

• The swing would gradually slow because the energy would be dissipated in the form of thermal energy.
• The pendulum would swing faster due to increased friction and thermal energy.
• The swing would immediately stop and energy would be destroyed. 
• The swing would continue at a steady rate because energy can't be destroyed.

The mass has 20 units of energy at its highest point.  Upon impact with the tent stake, 3 of the original units transform into thermal energy, 2 of the original units transform into sound energy.   Based on the law of the conservation of energy, how many of the original 20 units would transfer to the stake?

• 0 units
• 20 units
• 5 units
• 15 units

How do we know that energy was transferred to the nail?

• We know this because energy dissipated upon impact when the hammer struck the nail.
• We know this because the nail is moved by a force, which means mechanical energy was transferred to the nail.
• We know this because the nail exerts a force on the hammer which applies the force to drive it into the wood.
• There is no energy transferred in this situation.

The elephant and the mouse dove off of the diving board at the same time.  Who has the most gravitational potential energy?

• The mouse, he is less massive.
• The elephant he is more massive.
• The will both have equal potential energy.
• Neither will have potential energy.

Bobby Billy is standing on top of the mountain in the image.  Johnny Jimmy is standing on the grass in the image.  Both Bobby and Johnny have the same mass.  Who has more potential energy?

• Both Bobby and Johnny have the same amount of potential energy.
• Johnny has more potential energy because of his decreased height.
• Bobby has more potential energy because of the height he is standing off of the ground level.
• Due to dissipated energy, Johnny Jimmy has more potential energy.