Question

(i) Explain the meaning of the following equation of motion: v = u + at, where symbols have their usual meanings.
(ii) A body starting from rest travels with uniform acceleration. If it travels 100 m in 5 s, What is the value of acceleration?
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Answer 1

(i) The given equation, v = u + at is known as the first equation of motion. This equation means that if a body changes its velocity from 'u' to a certain value at a rate 'a' in a time interval 't', then the final velocity 'v' of the body can be obtained by the given equation, v = u + at. The final velocity can be calculated from the equation if the other three quantities are known.

(ii) Distance travelled by the body = 100 m

Time taken = 5 s

Initial velocity = 0 m/s

Using the second equation of motion, $s=ut+\frac{1}{2}a{t}^2$

$$\begin{gathered} \Rightarrow s=100\mathrm{m}=0+\frac{1}{2}\left(a\right)(5\mathrm{s}{)}^2 \\ \Rightarrow a=4\mathrm{m}/{\mathrm{s}}^2 \end{gathered}$$