Question

A bus started from rest and attains a velocity of 10m/s in 40 sec. The driver applies brakes and slows down the car at 5m/s in 10 sec. Find the acceleration of the car in both the cases

Answer 1

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

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

• Case-1

u = 0 m/s.

v = 10 m/s.

t = 40 seconds.

• Case-2

u = 10 m/s.

v = 5 m/s.

t = 10 seconds.

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

Case-1

From the acceleration formula.

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

substituting the values.

${a = \frac{10 - 0}{40}}$

${a = \frac{10}{40}}$

${a = \frac{1}{4}}$

${a = 0.25 m/s^2}$

$\huge{\boxed{\boxed{a = 0.25 m/s^2}}}$

so,the acceleration of bus is 0.25 m/s^2.

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Case-2

From the acceleration formula.

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

substituting the values.

${a = \frac{5 - 10}{10}}$

${a = \frac{-5}{10}}$

${a = \frac{-1}{2}}$

${a = -0.5m/s^2}$

$\huge{\boxed{\boxed{a = -0.5 m/s^2}}}$

so,the acceleration (deceleration) is 0.5 m/s^2.

Note:-

(-)ve sign indicates that bus is accelerating.