Motion and Forces, Conservation of energy Flashcards
(28 cards)
What does a horizontal line on a distance-time graph show?
The object is stationary.
What does a sloped straight line on a distance-time graph show?
The object is moving at constant speed.
What does a curved line on a distance-time graph indicate?
The object is accelerating or decelerating.
What does the gradient of a distance-time graph represent?
Speed.
What does a horizontal line on a velocity-time graph show?
Constant velocity.
What does a sloped line on a velocity-time graph represent?
Acceleration or deceleration.
What does the area under a velocity-time graph represent?
Distance travelled.
What is Newton’s First Law?
An object remains at rest or in constant motion unless acted on by a resultant force.
What is Newton’s Second Law about?
The greater the force, the greater the acceleration; the greater the mass, the smaller the acceleration.
What is Newton’s Third Law?
Every action has an equal and opposite reaction.
What is the difference between mass and weight?
Mass is the amount of matter in an object; weight is the force of gravity acting on it.
What affects an object’s weight?
Gravitational field strength.
What is terminal velocity?
The constant speed a falling object reaches when the force of air resistance equals the weight.
What is thinking distance?
The distance a vehicle travels during the driver’s reaction time.
What factors affect thinking distance?
Speed, tiredness, alcohol, drugs, distractions.
What is braking distance?
The distance a vehicle travels after the brakes are applied until it stops.
What factors affect braking distance?
Speed, road surface, weather, condition of tires and brakes.
What is stopping distance?
Thinking distance plus braking distance.
What is the law of conservation of energy?
Energy cannot be created or destroyed, only transferred or stored.
What is meant by a closed system?
A system where no energy enters or leaves; total energy stays constant.
Name four types of energy stores.
Thermal, kinetic, gravitational potential, elastic potential.
Name four ways energy can be transferred.
By heating, by waves, by electrical work, by mechanical work.
What is meant by energy dissipation?
Wasted energy, usually transferred as heat or sound to the surroundings.
What is efficiency?
A measure of how much input energy is usefully transferred.
