Question

Question 37:
(a) What is meant by the term ‘acceleration’ ? State the SI unit of acceleration.
(b) Define the term ‘uniform acceleration’. Give one example of a uniformly accelerated motion.

Lakhmir Singh Physics Class 9

Answer 1

(i) In physics or physical science,acceleration (symbol: a) is defined as the rate of change (or derivative with respect to time) of velocity. It is thus a vector quantity with dimension length/time². In SI units, accelerationis measured in meters/second² using an accelerometer.


(ii) Uniform or constant acceleration is a type of motion in which the velocity of an object changes by an equal amount in every equal time period. A frequently cited example of uniform accelerationis that of an object in free fall in auniform gravitational field. 1.) The motion of a freely falling body and a vertically thrown up body are theexample of uniform accelaration. 2.) The motion of a ball rolling down aninclined plane is another example ofuniform accelaration. a body has auniform accelaration if its velocity changes at a uniform rate.

Answer 2

acceleration means rate of change of velocity with respect to time. Its SI unit is m/s^2
uniform acceleration means a body covering a certain distance with equal velocity in equal amount of time velocity of a car.