What can you say about the motion of an object if its speed time graph is a straight line parallel to the time axis?

What can you say about the motion of an object whose distance-time graph is a straight line parallel to the time axis?

What is the nature of the distance-time graphs for uniform and non-uniform motion of an object?

A train starting from a railway station and moving with uniform acceleration attains a speed of 40 km h–1 in 10 minutes. Find its acceleration.

A bus decreases its speed from 80 km h–1 to 60 km h–1 in 5 s. Find the acceleration of the bus.

When will you say a body is in (i) uniform acceleration? (ii) non-uniform acceleration?