Forces and Motion

Question 1

Speed is distance travelled per unit time, a scalar, velocity is speed in a given direction, a vector. Average speed = total distance/total time

Question 2

Acceleration is a change in velocity per unit time, and can represent a change in speed or direction. A deceleration is a negative acceleration

Question 3

In a distance time graph :
An at rest object is a horizontal line
An object moving with a constant speed is any straight line
An accelerating object is an upwards curve
A decelerating object is a downwards curve
The speed at any point is the gradient of a distance time graph

Question 4

In a speed-time graph:
An object at rest in in the x-axis
An object moving with constant speed is a horizontal line
An accelerating object is an upwards line
A decelerating object is a downwards line
A constant acceleration is a straight line, a changing acceleration is a curve

Question 5

The acceleration of free fall for an object approaching Earth’s surface is approximately constant and is approximately 9.8m/s squared. Without drag, any object will continue to accelerate like this until it hits the ground. With the drag, the object will continue to accelerate until the weight and drag forces are balanced, and it moves at a constant speed

Question 6

Mass is a measure of the quantity of matter in an object. Weight is a gravitational force in anything that has mass. Weights and masses may be compared using a balance

Question 7

Gravitational field strength is force per unit mass. g=W/m. This is equivalent to the acceleration of free fall.