Unit 1 - Newton's Laws Flashcards
What causes a change in the motion of an object?
Forces acting on the object.
Which law explains motion involving speeding up, slowing down, or changing direction?
Newton’s Second Law of Motion.
What is ‘unchanging motion’?
When a body is at rest or moving at a steady speed in a straight line.
What type of forces are responsible for unchanging motion?
Balanced forces.
What happens when forces on an object are balanced?
The object remains at rest or continues to move at constant speed in a straight line.
What is ‘changing motion’?
Motion where the object is speeding up, slowing down, or changing direction.
What causes changing motion?
Unbalanced forces.
Give an example of unbalanced forces in action.
The lift-off of a space shuttle.
What is friction?
A force that opposes motion, present when two surfaces rub against each other.
Give two examples where friction is useful.
Soles of shoes for grip; car tires for turning and braking.
Why can friction be a nuisance?
It can waste energy and cause wear, e.g., in wheel axles.
How is energy transferred due to friction?
Kinetic energy is converted to thermal (heat) energy.
Formula for work done against friction?
Work Done = Frictional Force × Distance → Ew = F × d
What does Newton’s First Law state about a stationary object with balanced forces?
It will remain at rest.
What does Newton’s First Law say about a moving object with balanced forces?
It will continue moving at constant speed in a straight line.
What does Newton’s Second Law state?
Unbalanced Force = Mass × Acceleration → Fun = m × a
What kind of forces cause acceleration?
Unbalanced forces.
State Newton’s Third Law.
If object A exerts a force on B, B exerts an equal and opposite force on A.
What allows rockets to launch according to Newton’s Third Law?
Rocket exerts force on gases downward; gases exert equal force upward.
What is the difference between mass and weight?
Mass is the amount of matter (kg); weight is the gravitational force on mass (N).
Formula for weight?
Weight = Mass × Gravitational Field Strength → W = m × g
What is terminal velocity?
The constant speed when the upward force (air resistance) equals the downward weight.
What happens to a skydiver during freefall?
Accelerates until forces balance, then moves at terminal velocity.
What does Newton’s First Law explain about skydivers?
Balanced forces mean constant downward speed.
Why do car safety features use Newton’s Laws?
To reduce forces during crashes and minimize injuries.
How do seat belts protect you in a crash?
They stop motion and apply an opposite force, reducing deceleration.
How do airbags reduce injury?
By increasing the time to decelerate, reducing force.
What do crumple zones do?
Increase time for deceleration and absorb crash energy.
Why should drivers follow road safety rules even below the speed limit in bad conditions?
Poor conditions increase stopping distance and crash risk.
