In this post, we will solve a set of numerical problems based on the acceleration formula and related concepts (for class 9 students).
1) Acceleration = change in velocity/duration of time
2) Acceleration = force/mass
Acceleration Numericals for class 9
1 ) A car is moving with a velocity of 30 m/s. The driver accelerated it for 5 seconds and reached a velocity of 40 m/s. What is the acceleration?
Initial velocity = 30 m/s and final velocity is 40 m/s.
And the elapsed time = 5 seconds
Therefore, acceleration a = change in velocity/elapsed time = (40 -30) / 5 m/s2 = 2 m/s2
Acceleration is 2 m/s2 [Answer]
2 ) A car is moving with a velocity of 30 m/s. The driver applied brake for 3 seconds to bring it down to zero. What is the value of acceleration? Is it retardation?
Initial velocity =30 m/s and final velocity is 0 m/s.
And the elapsed time = 3 seconds
Therefore, acceleration a = change in velocity/elapsed time = (0-30) / 3 m/s2 = -10 m/s2
So, acceleration = -10 m/s2
The negative value of a tells that it’s actually retardation.
3 ) An automobile manufacturer decides to build a car that can accelerate uniformly from 0 to 27 m/s in 10 s. The car’s mass is to be about 1,000 kilograms. What is the force required?
First, we must determine the acceleration and then use Newton’s second law to find the force.
acceleration a = change in velocity/elapsed time = (27-0)/10 m/s2 = 2.7 m/s2
So the force needed to cause this acceleration is:
F = ma = 1,000 x 2.7 N = 2,700 N
4 ) A 10 N force is applied on an object of 10 kg. What will be the acceleration of the object?
Given, Force F =10 N
Mass = m = 10 kg
So, acceleration a = F/m = 10/10 m/s2 = 1 m/s2
Acceleration= 1 m/s2 (Answer)