Question

A car increases its speed from 20 km/h to 40 km/h in 10 seconds. What is its acceleration?

Answer 1

Hint: In this question we have been asked to calculate the acceleration of a car. It is given that the speed of a car is increased from 20 km/h to 40 km/h in 10 seconds. We know that rate of change of velocity or speed is given as acceleration. We also know that the relation between the initial velocity, final velocity, time, and acceleration is given by the second kinematic equation. Therefore, we shall use this equation to calculate the acceleration of the given car.
Formula used:-
\[v=u+at\]
Where,
V is the final velocity
U is the initial velocity
T is the time and
A is the acceleration

Complete step-by-step solution
It is given that the speed of a car increases from 20 km/h to 40 km/h. therefore, we can say that,
\[v=40km/h\] , \[u=20km/h\]. Also, it is given that time \[t=10\sec \]
Now, the units of time and velocities are different. Therefore, after the conversion of units
We get,
\[v=11.11m/s\] and \[u=5.5m/s\] …………… (1)
Now, from the second kinematic equation
We knew,
\[v=u+at\]
After substituting the values from (1)
We get,
\[11.11=5.5+10a\]
On solving
We get,
\[a=0.56m/{{s}^{2}}\]
Therefore, the acceleration of the given car is 0.56 metre per second squared.

Note: Kinematic analysis the process of measuring the kinematic quantities such as velocity and acceleration used to describe the motion. There are five main kinematic equations. If a body is moving with a constant acceleration, the kinematic equations may be used to determine the initial speed, final speed, acceleration, or distance covered by the object in unit time. It is required that some of the kinematic quantities be known to determine the others.