1 2 motion

Speed is the distance travelled per unit time.

False. Speed is a scalar quantity because it only contains magnitude.

Average speed is the total distance travelled divided by the total time taken.

The equation for calculating average speed is

Velocity describes both magnitude and direction of motion whereas speed describes only magnitude.

Velocity is defined as the rate of change of displacement with respect to time.

The equation for velocity is Where:

False. Velocity is a vector quantity because it includes direction.

Both speed and velocity are measured in metres per second (m/s).

The significance of negative velocity values indicates motion in the opposite direction.

Displacement is different from distance in calculating velocity because it accounts for direction.

The difference between speed and velocity is that speed is a scalar, while velocity is a vector as it includes direction.

The total distance is calculated from the average speed by multiplying the average speed by the total time taken.

Acceleration is the rate of change of velocity.

True. Acceleration measures the rate of change of velocity.

The equation for average acceleration is
Where:

Acceleration is measured in metres per second squared (m/s²).

You can find the change in velocity by obtaining the difference between final and initial velocity.

A positive acceleration indicates that the object is speeding up.

Acceleration is the change in an object's velocity over time.

Negative acceleration indicates that the object is slowing down.

Deceleration is negative acceleration, it shows an object is slowing down.

The acceleration of an object with constant velocity is zero.

Acceleration is calculated as the gradient of a velocity-time graph.

The direction of acceleration is represented by a positive or negative value.

A distance-time graph shows the distance travelled by a moving object over a period of time.

On a distance time graph, constant speed is represented by a straight line:

On a distance-time graph, changing speed is represented by a curved line.

The equation used to find the gradient of a distance-time graph is Where:

On a distance-time graph, the line with the smallest gradient has the slowest speed. This is the shallowest line (the orange line).

True. A flat, horizontal line on a distance-time graph shows that the object is stationary. The distance the object has travelled is not changing with time.

The object in this distance-time graph has an increasing speed. The distance it travels in each interval of time is increasing; therefore, the line curves upward.

A speed-time graph shows how the speed of a moving object varies with time.

Constant acceleration on a speed-time graph is represented by a straight, sloping line.

False. A gentle slope on a speed-time graph represents a small acceleration.

The speed-time graph shows decreasing acceleration. The change in speed per unit time decreases.

A flat, horizontal line indicates that the acceleration is zero, meaning the object is moving at a constant speed.

The area under a speed-time graph represents the distance travelled by the object.

The total area under a speed-time graph shows the total distance travelled. The total area is the sum of the areas of each enclosed section (triangle or rectangle).

The formula to calculate the area of a triangle is Where:

The formula to calculate the area of a rectangle is Where:

The area under a speed-time graph forms a rectangle.

False. A flat line on a speed-time graph indicates constant speed.

False. The starting speed is not zero because the line does not start from the origin.

Acceleration of free fall is the constant rate at which all objects fall in the absence of air resistance, typically denoted by the symbol and equal to approximately 9.81 m/s² near the surface of the Earth.

False. In the presence of air resistance different objects fall at different accelerations and not at *g. *In most Physics questions we assume that air resistance is negligible.

The value of the acceleration of free fall is *g *= 9.81m/s2

True. Acceleration of free fall remains constant regardless of an object's mass.

Terminal velocity is the constant speed reached by a falling object when the upward force of drag equals the downward force of weight, resulting in zero acceleration.

The equation for weight is Where:

Air resistance is the frictional force exerted by air particles on objects moving through air, which opposes the direction of motion.

Air resistance opposes the motion of objects falling through air, exerting an upward force that increases with the object's speed.

False. Air resistance increases as the speed of a falling object increases.

During free fall, weight acts downwards while air resistance acts upwards. As the speed of the object increases, air resistance increases until it equals the weight and terminal velocity is reached.

Terminal velocity occurs when the acceleration of a falling object becomes zero because the upward drag force equals the downward force of weight, resulting in a constant speed.

False. The air resistance changes with speed during the fall of a skydiver.

The acceleration of free fall is affected by the gravitational field strength. It is independent of the mass of the falling object.

Weight is the gravitational force exerted on an object with mass.