Answer:
D: 1.56
Explanation:
On a frictionless plane, W||=Wsin(θ). To push the brick up the plane, the car has to push with a force just greater than W||. To lift the brick directly, a force just greater than W must be used. The mechanical advantage is the ratio of the force needed to lift the brick directly to the force needed to lift the brick with the plane:
MA=Force needed to lift object without inclined plane/Force needed to lift object with inclined plane
MA=W/W||
MA=W/Wsin(θ)
MA=1/sin(40∘)
MA=1.56
