Question

5. A driver of a car travelling at 52 km h-l applies the brakes and
accelerates uniformly in the opposite direction. The car stops
in 5 s. Another driver going at 3 km h- in another car applies
his brakes slowly and stops in 10 s. On the same graph paper,
plot the speed versus time graphs for the two cars. Which of
the two cars travelled farther after the brakes were applied?​

Answer 1

Answer:

14.5

Explanation:

The speed time graph of both the cars are shown above.

(i) Distance covered by car moving at 52kmh  

−1

 (or 52×  

18

5

​  

=14.4ms  

−1

)

= area of ΔPOQ=  

2

1

​  

×PO×OQ=  

2

1

​  

×14.4×5

=36m

(ii) Distance covered by car moving at 3kmh  

−1

 (or 3×  

18

5

​  

=0.83ms  

−1

)

= area of ΔOLN=  

2

1

​  

×LO×ON=  

2

1

​  

×0.83×10=4.15m

∴ The car moving at 52kmh  

−1

 travels more distance on the application of brakes.