That is true Step by step:
What is the SI (metric) unit of FORCE?
with symbol ( N )
All the best !
NO net force is required to keep a moving object moving in a straight
line at a constant speed. In fact, if you apply ANY force to it, in ANY
direction, then its speed, its direction, or both must change, and its
velocity won't be uniform any more.
I know we never see this in our daily life. Whenever we see an object
moving, it always stops. That's because the net force on it is never zero ...
there's always some gravity or some friction acting on it. That's what you
have to put up with when you live on Earth.
The object keps going cause of wind friction
Going upstream against the current gives a net speed equivalent to the speed at still water minus the speed of the current. Consequently, the speed downstream gives a net speed equal to the speed at still water plus the speed of the current, making it travel faster. The solution is:
UPSTREAM
v = 20 - 1.5 = 18.5 km/h
t = 30 mins or 0.5 hours
distance = 18.5km/h (0.5 h) = 9.25 km
DOWNSTREAM
for the same distance of 9.25 km:
v = 20 + 1.5 = 21.5 km/h
t = 9.25km / 21.5 km/h = 0.43 hours or 25.8 mins = 26 mins --> FINAL ANS.
