Answer:
Explanation:
given,
cyclist ride 6.2 km east and then 9.28 km in the direction of 27.27° west of north and then 7.99 km west.
vertical component = 9.28 cos∅
= 9.28 cos 27.27°
= 8.24 km
horizontal axis component = 9.28 sin ∅
= 9.28 sin 27.27°
= 4.5 km
distance of the final point from the origin
= 7.99 -(6.2-4.5)
= 6.29 km
displacement
d = 10.37 km
b) 
θ = 37.36°
Potential energy = (weight) x (height)
After the car has been raised 2.5 meters, it has
(11,000) x (2.5) = 27,500 Joules
MORE potential energy than it had before it was lifted.
That's the energy that has to come from the work you do to lift it.
Since no mechanical process is ever 100% efficient, the work required
to accomplish this task is <em>at least 27,500 joules</em>.
There are some missing data in the text of the problem. I've found them online:
a) coefficient of friction dry steel piston - steel cilinder: 0.3
b) coefficient of friction with oil in between the surfaces: 0.03
Solution:
a) The force F applied by the person (300 N) must be at least equal to the frictional force, given by:
where
is the coefficient of friction, while N is the normal force. So we have:
since we know that F=300 N and
, we can find N, the magnitude of the normal force:
b) The problem is identical to that of the first part; however, this time the coefficienct of friction is
due to the presence of the oil. Therefore, we have:
