Activity 8.8 Class 9 Science Chapter 8 Motion

Answer:

Acceleration in the direction of motion.

Acceleration is a vector quantity. It shows the velocity is changing either its magnitude (like in linear motion) or changing direction as in circular motion or both (a mixed type).

When velocity is increasing with time, the acceleration is in the direction of the motion. Eg. a just started vehicle. E.g. an airplane taking off on the highway.

Acceleration in the direction opposite of motion

Its reverse is also true. When velocity decreases with time, the acceleration is in the opposite direction of the motion. E.g. a stopping vehicle.

Uniform acceleration

A real-life example of uniform acceleration in a free-falling body. The earth attract every particle with its gravitational pull. This pull creates an acceleration that is constant that is 9.8m/s^2.

Non-Uniform acceleration

non-Uniform acceleration is not so common in real life. Only a few things have non-uniform acceleration. One is an object moving in a circular motion with uniform speed. Here the speed remains the same but the velocity and acceleration are changing its direction with time. So, the acceleration become non-uniform. Movement of a ceiling fan, a spinning Teetotum, etc are examples of motion with non-uniform acceleration.

Next: Activity 8.9 Class 9 Science Chapter 8 Motion.

Activity 8.8 Class 9 Science Chapter 8 Motion

Ref: NCERT Class 9 Science Chapter 8.