Understanding Motion

• Motion refers to the change in position of an object with respect to its surroundings in a given period of time.

• When an object moves in a straight line with respect to its observer, it's in linear motion.

• When an object's distance from a certain point is constantly changing, it's in non-linear motion. Examples include circular and oscillating motion.

Distance, Displacement, Speed, and Velocity

• Distance is the total path travelled and has no direction, whereas displacement is the shortest distance from start to finish, and comes with a direction.

• Speed is how fast an object moves disregarding direction, while velocity is speed in a given direction.

• Velocity can be calculated by displacement divided by time.

• Average velocity and instantaneous velocity are two key concepts.

Acceleration

• Acceleration refers to the rate at which an object changes its velocity.

• An object is accelerating if it's changing direction even if its speed remains the same.

• Acceleration can be calculated by the change in velocity divided by the time taken for this change.

Graphs of Motion

• Motion is often plotted on displacement-time, velocity-time and acceleration-time graphs.

• On a displacement-time graph, the gradient indicates speed.

• On a velocity-time graph, the gradient indicates acceleration, while the area under the graph indicates displacement.

• On an acceleration-time graph, the area under the graph represents the change in velocity.

Newton's Laws of Motion

1. Newton's First Law states that an object will stay at rest or in uniform motion in a straight line unless acted upon by an external force.

2. Newton's Second Law states that the force exerted on an object equals its mass times its acceleration (F=ma).

3. Newton's Third Law states that for every action, there is an equal and opposite reaction.

Gravitational Force

• The gravitational force exerted on an object is dependent on its mass and the mass of other objects around it.

• While gravity pulls objects towards each other, their movement can resist this pull due to inertia or other opposing forces (like friction).

• The acceleration due to gravity near the surface of the Earth is approximately 10 m/s².

Practical Applications and Calculations

• These concepts of motion are used in everyday life, from driving to sports to the functioning of machinery.

• Practice calculating velocity, acceleration, force, and displacement using different equations of motion.