Question

You are out and about in the country and your father sees a rock that he really wants in the yard. Now you must get the very heavy rock into the back of a truck. The truck bed is 3 feet off the ground. Your father pulls out a 5-foot plank and begins to set up a ramp. At the same time, you have found a plank that is 8 feet long, and you show it to your father.

Which plank will give you the most mechanical advantage? Calculate the MA for each plank.

Answer 1

Step-by-step explanation:

Provided the planks are each strong enough to support the weight of the rock, the 8 ft plank will have a greater mechanical advantage.

The ideal (no friction) mechanical advantage for each ramp is

ME₈ = 8/3 = 2.67

ME₅ = 5/3 = 1.67