Question

plz answer fast with full solutions
class9 ch motion​

Answer 1

Answer: Approx 40m/s

Explanation:

given=

Speed 1 = 40Km=40000m

Speed 2 = 50Km=50000m

Total time taken= 2hrs = 7200sec

Average speed= Total Speed/Total Time

Avg. Speed= 40000+50000/7200

= 40006.9444444

Answer 2

FROM STOP A TO STOP B

v=40km/h=100/9m/s

s=s

t=t

t=s/v

t=s/100/9 m/s

t=9s/100 seconds

distance will be constant it wont change as he is moving in that place.

FROM STOP B TO STOP A

v=50km/h=125/9 m/s

s=s

t=t'

t=s/v

t'=s/125/9 m/s

t'=9s/125 seconds

AVERAGE SPEED=TOTAL DISTANCE COVERED/TOTAL TIME TAKEN(time from A TO B AND B TO A)

TOTAL DISTANCE=2s(FROM A TO B THE DISTANCE IS s AND FROM B TO A THE DISTANCE IS s SO THE TOTAL DISTANCE IS 2s)

AVERAGE SPEED=2s/t+t'

AVERAGE SPEED=2s/(9s/100+9s/125)

AVERAGE SPEED=2s/(45s+36s)

AVERAGE SPEED=2s/81 m/s