Question

A sports car accelerates from rest to 92 km/h in 5.1 s . What is its average acceleration in m/s2.

Express your answer using two significant figures.

Answer 1

$\huge{\underline{\underline{.........Answer.........}}}$

$\huge{\underline{Given:-}}$

u = 0 m/s.

v = 92 km/h.

t = 5.1 seconds.

Acceleration

It is rate of change of velocity of a body.

${S.I units :- m/s^2.}$

$\huge{\underline{Explanation:-}}$

As v is given in km/h it should be converted into m/s.

${92 km/h = 92 \times 5/18}$

Therefore,

${v = 5.1 \times 5}$ m/s.

Now from average acceleration formula

$\huge{\boxed{\boxed{a = \frac{v - u}{t}}}}$

substituting the values.

${a = \frac{5.1 \times 5 - 0}{5.1}}$

${a = \frac{5.1 \times 5}{5.1}}$

${a = 5 m/s^2}$

$\huge{\boxed{\boxed{a = 5 m/s^2}}}$

In two significant figures

$\huge{\boxed{\boxed{a = 5.0 m/s^2}}}$

so,the average acceleration is 5.0 m/s^2.