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What is the definition of work?
The amount of energy transferred.
What is efficiency?
The percentage of energy that is transferred into useful energy.
What type of energy does an object have if it has been lifted up?
Gravitational potential energy.
What is kinetic energy?
Energy that moving objects possess.
As a skydiver falls,what happens to gravitational energy?
The gravitational energy is transferred to kinetic energy.
State Hooke’s Law.
The force applied to a spring is proportional to the extension of the spring.
What is the spring constant ‘k’?
a property of a spring that tells you how stiff it is.
What is the elastic limit?
The point at which the spring no longer obeys Hooke’s Law.
How is the elastic limit identified on a force-extension graph?
It is the point at which the line begins to curve and is no longer straight.
What happens to a spring once you have hit the elastic limit?
It will not go back to its original length once the force has been removed.
What does the gradient of the force-extension graph represent?
The spring constant.
What does the area underneath the force-extension graph represent?
The work done on the spring.
State three safety features on a vehicle.
air bag, seat belt, and crumple zone.
What is the crumple zone?
The area at the front of the car that is designed to crumple on impact.
Explain how each of the safety features prevent injury.
Each safety feature increases the time it takes to stop during a collision. This decreases the rate of deceleration which reduces the force on the driver/passenger inside the vehicle.
State 4 ways that you can improve the efficiency of a vehicle and reduce:
inertial losses?
aerodynamic losses?
idling losses?
rolling resistance losses?
reduce mass
make the vehicle more streamlined (aerodynamic)
have the engine switch off automatically when the car is sitting in traffic.
ensure the tyres are pumped to the correct pressure.
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