A bus decreases its speed from 80, km, h^{-1} to 50 ,km h ^{-1} in 4, s . acceleration of bus.

English

Gujarati

Hindi

7. MOTION

easy

A bus decreases its speed from $80\, km\, h^{-1}$ to $50 \,km h ^{-1}$ in $4\, s$. Find the acceleration of the bus.

Option A

Option B

Option C

Option D

Solution

Given $v=50 km h ^{-1}=50 \times \frac{5}{18}=\frac{125}{9} m s ^{-1}$

$u=80 km h ^{-1}=80 \times \frac{5}{18}=\frac{200}{9} m s ^{-1}$

$t=4 s$

Using the expression $v=u+a t,$ we have

$a=\frac{v-u}{t}=\frac{125-200}{9 \times 4}=-2.083 m s ^{-2}$

Standard 9

Science

Share

Similar Questions

When is the acceleration $(i)$ positive $(ii)$ negative ?

medium

$(a)$ Derive second equation of motion $S=u t+\frac{1}{2} a t^{2}$ graphically where the symbols have their usual meanings.

$(b)$ A car accelerates uniformly from $18\, km h ^{-1}$ to $36\, km h^{-1}$ in $5$ seconds. Calculate the acceleration and the distance covered by the car in that time.

hard

A car manufacturer advertises that the brakes are so perfect that the car stops instantaneously. Comment.

easy

$(a)$ Which type of motion is represented by the velocity$-$time graph shown below ?

$(b)$ Name the physical quantity which can be calculated by the area of rectangle $OABC$.

$(c)$ What does the straight line $AB$ represents ?

easy

What is the slope of the displacement $-$ time graph when the body has uniform motion ?

easy