When do you say a body is in
(i) uniform acceleration, and
(ii) variable acceleration?
(i) Uniform acceleration:
When an object travels in a straight line and its velocity changes by equal amounts in equal intervals of time, the object is said to be in ‘uniform acceleration’.
For example, a body falling freely to the ground has a uniform acceleration of 9.8 m/s2 as its velocity increases by 9.8 m/s after every one second.
(ii) Variable acceleration:
When the velocity of an object changes by unequal amounts in equal intervals of time, the object is said to have ‘variable acceleration’.
For example, if the speed of a car travelling along a straight road increases by unequal amounts, then the car is moving with non-uniform acceleration.
What are the uses of graphical study of motion?
What is velocity-time graph of a body? Draw velocity-time graphs for
(i) a body moving with uniform velocity,
(ii) a body moving with uniform acceleration, and
(iii) a body moving with variable acceleration.
What is distance-time graph of a body? Draw distance-time graphs for,
(i) a stationary body,
(ii) a body moving with uniform velocity, and
(iii) a body moving with variable velocity.
A train moves with a speed of 30 km/h in the first 15 minutes, with another speed of 40 km/h in the next 15 minutes and then with a speed of 60 km/h in the last 30 minutes. Calculate the average speed of the train for this journey.
