Energy Conversion and Conservation

Which statement best describes energy conversion?

• Stopping energy transfer between objects

• Destroying energy during physical processes

• Creating new energy from raw materials

• Changing energy from one form to another

According to the law of conservation of energy, what can energy do in a closed system?

• Increase without external input

• Be created from zero mass

• Disappear during frictional motion

• Transform between different forms

As a pole vaulter runs down the track, which type of energy is primarily increasing?

• Electrical energy in the shoes

• Chemical energy in the pole

• Thermal energy of the runway

• Kinetic energy of the athlete

When the pole bends after planting, the athlete’s kinetic energy primarily converts to which form?

• Sound energy from the crowd

• Magnetic potential in spikes

• Gravitational potential in air

• Elastic potential in the pole

As the pole recoils and straightens, which energy change propels the vaulter upward?

• Thermal to chemical energy

• Electrical to magnetic energy

• Elastic to kinetic energy

• Nuclear to thermal energy

At the highest point of the vault, the athlete’s energy is mostly which form?

• Chemical stored energy

• Thermal waste heat

• Elastic potential energy

• Gravitational potential energy

When pole vaulting, during descent after the peak, which transformation occurs?

• Potential converts to kinetic

• Kinetic converts to elastic

• Thermal converts to chemical

• Electrical converts to magnetic

Which statement about efficiency is most accurate?

• Efficiency eliminates conservation limits

• Efficiency increases energy creation

• All ideal systems are perfectly efficient

• No real conversion is 100% efficient

Which factor commonly reduces energy conversion efficiency in machines?

• Friction and heat loss

• High-quality insulation

• Gravitational balancing

• Closed-system design

Which simple action can reduce energy loss in moving parts?

• Adding extra joints and gears

• Increasing mass of components

• Minimizing friction with lubrication

• Using rougher contact surfaces