Question

Object covers 120m in first 5 sec and 60m in next 4 sec what is average speed in m/s and km/hr

Answer 1

Average Speed = (120+60)/(5+4)= 20m/s
in km/h, the average speed = 72km/h

Answer 2

Average speed=total distance travelled/total time taken
so,
for m/s
lets take,
average speed = A.S
total time taken=T.T
total distance=T.D
so,
TT=5+4sec.=9sec.
TD=120+60m=180m
AS=?
AS=TD/TT
AS=180m/9sec.
=>AS=20m/sec.
for km/hr,
TD=0.18km
TT=0.0025hr
AS=?
we know ,
AS=TD/TT
so,
AS=0.18km/0.0025hr
=>AS=72km/hr