Question

Which graph illustrates constant speed and velocity?

Answer 1

The correct graph is D.

The graph A is a straight line sloping downwards and it shows that the speed of the body is decreasing at a constant rate. Therefore, this s a graph of a body that is under a constant deceleration.

The graph B is a straight line which slopes upwards. Hence the graph shows that the speed of the body increases at a constant rate. Therefore, this is a graph of a body that is accelerating at a constant rate.

The graph C is curved line, which curves upwards. The slope of the curve increases with time. This is therefore, a graph of a body which is under increasing acceleration.

The graph D, however is a straight line parallel to the time axis. The speed of the body has the same value at all times. Therefore, Graph D is the graph which shows the motion of a body with constant speed.

Answer 2

Answer choice D is correct.

When you are thinking about a "constant" on a graph, it usually means that is is a straight line that is either horizontal or vertical. In this case the only graph that as both a constant speed and velocity is D which is why it is correct.

A has a negative constant acceleration

B has a positive acceleration

C is not constant, but is moving at a positive acceleration.

Hope this helps some!