Acceleration

Understanding Acceleration

• Acceleration is defined as the rate of change of velocity. It measures how quickly an object’s speed or direction of motion changes.
• It is a vector quantity, meaning it has both magnitude (size) and direction.
• The SI unit for acceleration is metres per second squared (m/s²).

Calculating Acceleration

• Acceleration can be calculated using the formula: a = Δv/t, where ‘a’ is acceleration, ‘Δv’ is change in velocity, and ‘t’ is time.
• If velocity and time are measured in m/s and seconds, respectively, acceleration will be measured in m/s².

Acceleration Due to Gravity

• All objects near the earth’s surface experience an acceleration due to gravity. This is known as the gravitational field strength and has a value of approximately 9.8 m/s².
• When an object is in free fall (not subject to any other forces such as air resistance), it will accelerate downwards at this rate.

Graphical Representation of Acceleration

• Acceleration can be represented graphically using a velocity-time graph.
• The slope of the line on a velocity-time graph represents the acceleration of the object.
• The area under the graph line represents the distance travelled by the object.

Effects of Forces on Acceleration

• A force applied to a body causes it to accelerate in the direction of the force.
• According to Newton’s second law, the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass (this is summarised in the equation F=ma).
• If more than one force acts on an object along a single line of action, the forces can be added together to give the resultant force. The net force will then determine the object’s acceleration.