Answer:
3.75 hours
Explanation:
By 
where v is the velocity (or speed in this case)
d is the distance travelled
t is the time taken

Therefore it takes 3.75 hours for the bus to travel 150 km and 40 km/hr.
For example science has discovered many amazing things like atoms,molecules which led to the development of nuclear reactors etc. Challenges would be like trying to prove theories like evolution for 100 of years trying to discover all the stuff we still don’t know exists all the mysteries of life. A lot of science is still theory we can’t prove some things until we have more advanced technology etc.
2a for example the first one,2sec. You know that every second it moves 3metres further. So 2x3=6 but you start at 0.50m so 6+0.50=6.5
Answer:
Explanation:
Normal length of spring = 28.3 cm
stretched length of spring = 38.2 cm
length of extension = 38.2 - 28.3 = 9.9 cm
= 9.9 x 10⁻² m
force applied to stretch = .55 x 9.8 ( mg )
= 5.39 N
Force constant = force applied / extension
= 5.39 / 9.9 x 10⁻²
= .5444 x 10² N /m
= 54.44 N/m