When is the acceleration taken as negative?
Acceleration is taken as negative if it is in the direction opposite to the direction of velocity.
Can a body have constant speed but variable velocity?
Yes, e.g. a body in uniform circular motion has constant speed but due to the change in the direction of motion, its velocity changes at every point.
A body is moving with a velocity of 10 m/s. If the motion is uniform, what will be the velocity after 10 s?
As the motion is uniform, the velocity remains 10 m/s after 10 s.
Does the speedometer of a car measure its average speed?
No. It measures its instantaneous speed.
When do the distance and displacement of a moving object have the same magnitude?
The magnitude of distance and displacement of a moving object are same when the object moves along the same straight line in the same fixed direction.
Can the displacement be greater than the distance travelled by an object?
No, it is always either equal to or less than the distance travelled by the object.
If the displacement of a body is zero, is it necessary that the distance covered by it is also zero?
No. When the body comes back to the same position after travelling a distance, its displacement is zero though it has travelled some distance.
What indicates the motion of the earth?
The phenomenon like day and night indicates the motion of the earth.
What is the simplest type of motion?
Motion in a straight line.
What is essential to describe the position of an object?
We need to specify a reference point called the origin.