Science - Physics: Newton Rules

Physics Newton Rules – What is distance?

The total length of the path travelled by an object, measured in metres (m)

Physics Newton Rules – What is displacement?

The straight-line distance and direction from an object's starting point to its ending point, measured in metres (m)

Physics Newton Rules – What is the difference between distance and displacement?

Distance measures the entire path travelled, while displacement measures the change in position and includes direction

Physics Newton Rules – What is speed?

The distance travelled per unit of time, measured in metres per second (m/s)

Physics Newton Rules – What is velocity?

The rate of change of displacement, including direction, measured in metres per second (m/s)

Physics Newton Rules – What is the difference between speed and velocity?

Speed is a scalar quantity with magnitude only, while velocity is a vector quantity with both magnitude and direction

Physics Newton Rules – What is the equation for average speed?

Average speed = total distance ÷ total time

Physics Newton Rules – How do you calculate average speed?

Divide the total distance travelled by the total time taken

Physics Newton Rules – What is the equation for average velocity?

Average velocity = displacement ÷ time taken

Physics Newton Rules – What does the gradient of a distance-time graph represent?

Speed

Physics Newton Rules – How do you calculate speed from a distance-time graph?

Gradient = change in distance ÷ change in time

Physics Newton Rules – What does a horizontal line on a distance-time graph represent?

The object is stationary because its distance is not changing

Physics Newton Rules – What does a straight upward-sloping line on a distance-time graph represent?

The object is moving away from its starting point at a constant speed

Physics Newton Rules – What does a steeper line on a distance-time graph represent?

A greater speed

Physics Newton Rules – What does a downward-sloping line on a distance-time graph represent?

The object is returning towards its starting point

Physics Newton Rules – What is Newton's First Law of Motion?

An object remains at rest or continues moving at a constant velocity unless acted on by an unbalanced external force

Physics Newton Rules – What is inertia?

The tendency of an object to resist changes in its state of motion

Physics Newton Rules – What factors affect an object's inertia?

Its mass; objects with greater mass have greater inertia

Physics Newton Rules – How does Newton's First Law explain why passengers move forwards when a car suddenly stops?

Their bodies continue moving forwards due to inertia, even though the car has stopped

Physics Newton Rules – What happens to an object when the forces acting on it are balanced?

Its motion does not change; it remains stationary or continues at a constant velocity

Physics Newton Rules – What happens when an unbalanced force acts on an object?

The object accelerates, meaning its speed or direction changes

Physics Newton Rules – What is the difference between balanced and unbalanced forces?

Balanced forces have a net force of zero, while unbalanced forces produce a non-zero net force

Physics Newton Rules – What is the net force?

The overall force acting on an object after all forces are combined, measured in newtons (N)

Physics Newton Rules – How do you calculate net force when forces act in the same direction?

Add the forces together

Physics Newton Rules – How do you calculate net force when forces act in opposite directions?

Subtract the smaller force from the larger force; the net force acts in the direction of the larger force

Physics Newton Rules – What is Newton's Second Law of Motion?

An object's acceleration is directly proportional to the net force and inversely proportional to its mass

Physics Newton Rules – What is the equation for Newton's Second Law?

Net force = mass × acceleration (F = ma)

Physics Newton Rules – What is the unit of force?

Newtons (N)

Physics Newton Rules – What is the unit of acceleration?

Metres per second squared (m/s²)

Physics Newton Rules – How does increasing the net force affect acceleration if mass stays constant?

Acceleration increases because force and acceleration are directly proportional

Physics Newton Rules – How does increasing mass affect acceleration if net force stays constant?

Acceleration decreases because mass and acceleration are inversely proportional

Physics Newton Rules – How can you calculate acceleration using Newton's Second Law?

Acceleration = net force ÷ mass (a = F ÷ m)

Physics Newton Rules – How can you calculate mass using Newton's Second Law?

Mass = net force ÷ acceleration (m = F ÷ a)

Physics Newton Rules – What is a free-body diagram?

A diagram showing all the forces acting on a single object using labelled arrows

Physics Newton Rules – What does the length of an arrow represent in a free-body diagram?

The relative size or magnitude of the force

Physics Newton Rules – What direction should a force arrow point?

In the direction the force acts

Physics Newton Rules – What forces commonly act on an object resting on a horizontal surface?

Weight acts downwards and the normal force acts upwards

Physics Newton Rules – What is weight?

The gravitational force acting on an object, directed towards the centre of the attracting body

Physics Newton Rules – What is the normal force?

The support force exerted by a surface on an object in contact with it

Physics Newton Rules – What is friction?

A force that opposes motion or attempted motion between surfaces in contact

Physics Newton Rules – What is air resistance?

A force that opposes an object's movement through air

Physics Newton Rules – What happens when an object is pushed with a force greater than friction?

There is an unbalanced force, so the object accelerates in the direction of the net force

Physics Newton Rules – What happens when an object has equal forces acting in opposite directions?

The net force is zero, so its motion does not change

Physics Newton Rules – What is Newton's Third Law of Motion?

For every action force, there is an equal and opposite reaction force

Physics Newton Rules – What are action-reaction force pairs?

Two equal and opposite forces that act on different objects during an interaction

Physics Newton Rules – Why do action-reaction forces not cancel each other out?

They act on different objects, rather than on the same object

Physics Newton Rules – What are the two key features of an action-reaction pair?

They are equal in magnitude, opposite in direction and act on different objects

Physics Newton Rules – How does Newton's Third Law explain walking?

Your foot pushes backwards on the ground, and the ground pushes forwards on your foot

Physics Newton Rules – How does Newton's Third Law explain a rocket launching?

The rocket pushes exhaust gases backwards, and the gases push the rocket forwards

Physics Newton Rules – How does Newton's Third Law explain swimming?

A swimmer pushes water backwards, and the water pushes the swimmer forwards

Physics Newton Rules – How does Newton's Third Law explain a ball bouncing off a wall?

The ball pushes on the wall, and the wall pushes back on the ball with an equal and opposite force

Physics Newton Rules – How do seatbelts demonstrate Newton's First Law?

They prevent passengers from continuing forwards due to inertia when a car suddenly stops

Physics Newton Rules – How does Newton's Second Law explain why a heavier car needs more force to accelerate at the same rate?

A greater mass requires a greater net force to produce the same acceleration

Physics Newton Rules – How do all three of Newton's Laws apply to a moving car?

First Law: inertia resists changes in motion; Second Law: net force determines acceleration; Third Law: tyres push backwards on the road and the road pushes the car forwards

Physics Newton Rules – How do all three of Newton's Laws apply to a rocket?

First Law: it remains at rest until an unbalanced force acts; Second Law: the net force causes acceleration; Third Law: exhaust gases are pushed backwards and the rocket moves forwards

Physics Newton Rules – What is the relationship between net force and acceleration?

Acceleration occurs in the direction of the net force and increases as net force increases, if mass remains constant

Physics Newton Rules – What happens when an object is falling and air resistance is less than its weight?

There is a net downward force, so the object accelerates downwards

Physics Newton Rules – What happens when a falling object reaches terminal velocity?

Air resistance equals weight, so the net force is zero and the object falls at a constant velocity

Physics Newton Rules – How can you identify whether an object is accelerating?

Its speed, direction or both are changing