Question

Q 4. The velocity-time graphs of a car and a scooter are shown in the figure. (i) The difference between the distance travelled by the car and the scooter in 15 s and (ii) the time at which the car will catch up with the scooter are, respectively.
(1) 112.5 m and 15 s
(2) 337.5 m and 25 s
(3) 112.5 m and 22.5 s
(4) 225.5 m and 10 s

Answer 1

Explanation:

The velocity-time graphs of a car and a scooter are shown in the figure. (i) the difference between the distance travelled by the car and the scooter in 15s and  (ii) the time at which the car will catch up with the scooter are, respectively





A

337.5m and 25s

B

225.5m and 10s

C

112.5m and 22.5s

D

11.2.5m and 15s

Solution

Correct option is

C

112.5m and 22.5s

The distance traveled in 15 seconds by both will be given by area under curve.

For car, s1=21×15×45  

              s1=337.5m

For scooter, s2=15×30

                    s2=450

s1−s2=112.5m

Suppose after time t, they will meet, then distance traveled by both of them will be equal.

30t=21×15×45+45×(t−15) 

30t=337.5+45t−675

15t=337.5

t=22.5s