Question

What is the acceleration experienced by a car that takes 10s to reach 27m/s from rest?

Answer 1

As a first step, you could read the question clearly and hence note down the values given in the question. Since this is a very basic question, you could simply recall the definition of acceleration and hence the mathematical expression could be derived from the same. We could then do simple substitution to get the acceleration of the body.

Formula used:
Acceleration,
$a=\dfrac{v-u}{t}$

Complete step-by-step answer:
In the question, we are given the case of a car that starts from rest and reaches a velocity of 27m/s within the duration of 10s. We are asked to find the acceleration of this car.
Let us firstly note down the information from the question for making it easy to solve.
We are clearly mentioned that the car is starting from rest, so we could say that this car has zero velocity. That is,
$u=0m{{s}^{-1}}$
Now this car is being accelerated to certain velocity. So, we could take that velocity as the final velocity of the car for the motion under consideration. That is,
$v=27m{{s}^{-1}}$
Now, we could recall the definition of acceleration of a body. Acceleration of a body is defined as the time rate of change of velocity. Mathematically, it is given by,
$a=\dfrac{v-u}{t}$
Now we could simply substitute the given values to get,
$a=\dfrac{27-0}{10}$
$\therefore a=2.7m{{s}^{-2}}$
Therefore, we found the acceleration of the car mentioned in the question to be$2.7m{{s}^{-2}}$.

Note: One should be well aware of this fact that acceleration shouldn’t necessarily be always positive. It can be positive and also negative. A positive acceleration would mean that the velocity of the body is being increased and negative acceleration would directly mean that the body is slowing down.