Question

6. A car covered the first 400 m distance with a speed of
8 m/s, the next 1200 m with a speed 12 m/s and the last
360 m with a speed of 12 m/s. Calculate the average speed
of the car.​

Answer 1

Answer:

9.8 m/s

Explanation:

Average speed =  

time taken to travel the distance

Total distance travelled

​  

 

Time taken to travel the distance 400 m=  

8

400

​  

=50 s

Time taken to travel the distance 1200 m=  

10

1200

​  

=120s

Time taken to travel the distance 360 m=  

12

360

​  

=30 s

Total distance travelled =400+1200+360=1960 m

Total time to travel =50+120+30=200 s

Average speed =  

200

1960

​  

=9.8 m/s

Answer 2

d1=400m
d2=120m
d3=360m
s1=8m/S
s2=12m/s
s3=12m/S

t1=400/8=50s
t2=1200/12=100s
t3=360/12=30s

total distance =400+1200+360=1960m

total time=50+100+30=180s
Average speed=1960/180=98/9 m/S

Therefore, the average speed of the car is 98/9m/s