i understand the part A already
but for B and C
i thought the formula for power is work done / time
so its 50/0.25 =200?
power = 200?
part C : since the horizontal force is 200n
then the work done is 50 so fiction suppose to be 200-50 =
150 ?
time is not 0.25 what.
0.25 means 0.25 metres moved in one sec. So when they asked per
sec it means 0.25* 200
if you wanna know why and you cannot rationalise it. This is
how:(write it down cos thsi is complicating when you write it out
in words)
distance/speed
= time
work done = distance * force
power = work done / time
power = distance * force / (distance/speed)
=
force * speed
Just know that constant speed means 0 net force due to the
formula. and 0 net force must mean friction is = force applied.
