Physics-Motion and energy

dt graphs

A distance-time graph shows how far something travels over a period of time. The vertical axis of a distance-time graph is the distance travelled from the start. The horizontal axis is the time from the start. Features of the graphs. When an object is stationary, the line on the graph is horizontal. When an object is moving at a steady speed in a straight line, the line on the graph is straight but sloped.Note that the steeper the line, the faster the object is travelling.

difference between speed and velocity

Average speed is distance divided by time. Velocity is speed in a given direction. Acceleration is change in velocity divided by time. Movement can be shown in distance-time and velocity-time graphs.

v-t graphs

The velocity of an object is its speed in a particular direction. Two cars travelling at the same speed but in opposite directions have different velocities. A velocity-time graph shows the speed and direction an object travels over a specific period of time. Velocity-time graphs are also called speed-time graphs. The vertical axis of a velocity-time graph is the velocity of the object. The horizontal axis is the time from the start. Features of the graphs When an object is moving with a constant velocity, the line on the graph is horizontal. When the horizontal line is at zero velocity, the object is at rest. When an object is undergoing constant acceleration, the line on the graph is straight but sloped. Curved lines on velocity-time graphs also show changes in velocity, but not with a constant acceleration or deceleration. The diagram shows some typical lines on a velocity-time graph.

speed = distance/time b.

average speed is measured in metres per second, m/s distance moved is measured in metres, m time taken is measured in seconds, s

A quantity that has magnitude but no particular direction is described as scalar. A quantity that has magnitude and acts in a particular direction is described as vector.

distance speed time power energy Scalar quantities change when their magnitude changes.