Answer:252 miles
Explanation:
Given
During his way to mountain it took 7 hr to drive
and during his return trip it took 4 hr to return
Let x be the distance between home and mountain
average speed for return is 27 miles per hour faster than his former trip
let v be the speed on his way to mountain thus v+27 is his return speed
thus ----1
for return trip
-----2
divide 1 & 2
thus
1. 12.75 J
Assuming that the force applied is parallel to the ramp, so it is parallel to the displacement of the cart, the work done by the force is
where
F = 15 N is the magnitude of the force
d = 85 cm = 0.85 m is the displacement of the cart
Substituting in the formula, we get
2. 10.6 N
In this part, the cart reaches the same vertical height as in part A. This means that the same work has been done (because the work done is equal to the gain in gravitational potential energy of the object: but if the vertical height reached is the same, then the gain in gravitational potential energy is the same, so the work done must be the same).
Therefore, the work done is
However, in this case the displacement is
d = 120 cm = 1.20 m
Therefore, the magnitude of the force in this case is