# 5.1 and 5.2 Flashcards

Define linear motion + give 2 track athletics examples

Motion in a straight or curved line, with all body parts moving the same distance, at the same speed in the same direction, e.g. 100m or 200 metres

The name of Newton’s 1st Law of Motion

The law of inertia

Define inertia

The resistance an object has to a change in its state of motion

Describe Newton’s 1st Law of motion

An (external) force is required to change the state of motion

What determines the inertia of an object

Its mass

The name of Newton’s 2nd law of motion

The law of acceleration

Describe Newton’s 2nd law of motion

The magnitude / size + direction of the force determines the magnitude and direction of the acceleration + the rate of acceleration is directly proportional to the size of the force causing the change

The equation used to calculate the size of a force

Force (N) = mass (KG) x acceleration (m/s^2), or F = ma

The name of Newton’s 3rd law of motion

The law of action / reaction

Describe Newton’s 3rd law of motion

For every action / force, there is an equal + opposite reaction / force

A ground reaction force (GRF)

The force exerted by the ground on the body in contact with it

Define a scalar quantity

When measurements are described in terms of just their size / magnitude (not direction)

2 examples of scalar quantities

Speed + distance

Define speed

The rate of change of position

The formula for calculating speed

Speed (m/s) = distance (m) / time (s)

Define distance

The length of a path that a body follows when moving from one position to another

What unit you should give the speed in if the question gives the distance in Km and the time in hours

Km/h

Where the line on your distance/time graph should finish for an out and back journey

At the bottom / x-axis

Define centre of mass

The point of balance/concentration of mass of a body

The effect that raising our arms has on the centre of mass of our body

It raises it

Where in the body the centre of mass of a person is normally when they’re standing

In the hip region

What characteristic of an individual determines their centre of mass

Gender