Distinguish speed and velocity.

A motorcycle travelling at 20ms^-1 has an acceleration of 4ms-2. What does it explains about the velocity of the motorcycle.

Complete of following sentences

a. The acceleration of the body that moves with a uniform velocity will be ________

b. A train travels from A to station B with a velocity of 100 km/h and returns from station B to station A with a velocity of 80km/h. Its average velocity during the whole journey in ______________ and its average speed is ____________

What is meant by negative acceleration?

A boy moves along the path ABCD. What is the total distance Covered by the boy? What is his net displacement?