Forces

Define distance (distance is…)

Distance is the total length of the path an object travels

Define displacement (displacement is…)

Displacement is the straight-line distance from start to finish in a specific direction

Define speed (speed is…)

Speed is the distance travelled per unit time

Define velocity (velocity is…)

Velocity is speed in a given direction

Define acceleration (acceleration is…)

Acceleration is the rate of change of velocity per unit time

State the symbol for distance (the symbol is…)

The symbol for distance is s

State the symbol for speed (the symbol is…)

The symbol for speed is v

State the symbol for time (the symbol is…)

The symbol for time is t

State the symbol for acceleration (the symbol is…)

The symbol for acceleration is a

Write the equation for speed (the equation is…)

Speed = distance ÷ time

Write the equation for distance (the equation is…)

Distance = speed × time

Write the equation for time (the equation is…)

Time = distance ÷ speed

Write the equation for acceleration (the equation is…)

Acceleration = change in velocity ÷ time

Define Δv (Δv is…)

Δv is the change in velocity

State the SUVAT equation linking velocities and distance (the equation is…)

v² − u² = 2as

Explain what a distance–time graph shows (it shows…)

It shows how distance changes over time

Describe a horizontal line on a distance–time graph (it means…)

It means the object is stationary

Describe a straight sloping line on a distance–time graph (it means…)

It means constant speed

Describe a curved line on a distance–time graph (it means…)

It means changing speed

Explain what the gradient of a distance–time graph represents (it represents…)

It represents speed

Explain what a velocity–time graph shows (it shows…)

It shows how velocity changes over time

Describe a horizontal line on a velocity–time graph (it means…)

It means constant velocity

Describe a sloping line on a velocity–time graph (it means…)

It means acceleration or deceleration

Explain what the gradient of a velocity–time graph represents (it represents…)

It represents acceleration

Explain what the area under a velocity–time graph represents (it represents…)

It represents distance travelled

Define mass (mass is…)

Mass is the amount of matter in an object

Define weight (weight is…)

Weight is the force acting on a mass due to gravity

Write the equation for weight (the equation is…)

Weight = mass × gravitational field strength

State the unit of weight (weight is measured in…)

Weight is measured in newtons (N)

State the unit of mass (mass is measured in…)

Mass is measured in kilograms (kg)

State the unit of gravitational field strength (g is measured in…)

g is measured in N/kg

State the value of g on Earth (g is…)

g is approximately 9.8 N/kg

Explain the difference between mass and weight (mass…

weight…)

Define resultant force (resultant force is…)

Resultant force is the single force that has the same effect as all forces combined

State Newton’s first law (Newton’s first law states…)

An object remains at rest or constant velocity unless acted on by a resultant force

State Newton’s second law (Newton’s second law states…)

Resultant force = mass × acceleration

Write the equation for Newton’s second law (the equation is…)

F = m × a

State Newton’s third law (Newton’s third law states…)

When two objects interact they exert equal and opposite forces

Define inertia (inertia is…)

Inertia is the tendency of an object to resist changes in motion

Define drag (drag is…)

Drag is the resistive force of a fluid acting opposite to motion

Define air resistance (air resistance is…)

Air resistance is a type of drag acting on objects moving through air

Define terminal velocity (terminal velocity is…)

Terminal velocity is the constant speed reached when forces are balanced

Explain how a falling object reaches terminal velocity (it reaches it because…)

Air resistance increases until it equals weight

Describe motion before terminal velocity (before terminal velocity…)

Weight > air resistance so the object accelerates

Describe motion at terminal velocity (at terminal velocity…)

Forces are balanced so the object moves at constant speed

Define a scalar quantity (a scalar is…)

A scalar has magnitude only

Define a vector quantity (a vector is…)

A vector has magnitude and direction

Give an example of a scalar (an example is…)

Speed is a scalar

Give an example of a vector (an example is…)

Velocity is a vector

Define deceleration (deceleration is…)

Deceleration is negative acceleration

Explain how to find speed from a graph (you find it by…)

You find it by calculating the gradient of a distance–time graph

Explain how to find acceleration from a graph (you find it by…)

You find it by calculating the gradient of a velocity–time graph

Explain how to find distance from a velocity–time graph (you find it by…)

You find it by calculating the area under the graph

State typical walking speed (walking speed is…)

Walking speed is about 1.5 m/s

State typical running speed (running speed is…)

Running speed is about 3 m/s

State typical cycling speed (cycling speed is…)

Cycling speed is about 6 m/s

Define uniform acceleration (uniform acceleration is…)

Uniform acceleration is constant acceleration

Define free fall (free fall is…)

Free fall is motion under gravity alone

Explain why g = a in free fall (because…)

Because weight is the only force so acceleration equals gravitational field strength

Define friction (friction is…)

Friction is a force opposing motion between surfaces

Explain how friction affects motion (it affects motion by…)

It reduces speed and causes energy dissipation

Define momentum (momentum is…)

Momentum is mass × velocity

State the unit of momentum (momentum is measured in…)

Momentum is measured in kg m/s

Define impulse (impulse is…)

Impulse is change in momentum