Question

Ellen needs to move a heavy box across the floor and then place it on a shelf that is four feet above the floor. Which use of machines would most likely require the least amount of force in order to get the box on the shelf?
sliding the box up an inclined plane to the shelf
rolling the box up an inclined plane on a cart
sliding the box across the floor and then lifting it using a pulley
rolling the box across the floor in a cart and then using a pulley

Answer 1

Option B is correct: Rolling the box up an inclined plane on a cart.

When using the inclined, Ellen needs to overcome frictional force and the weight component of the box along the ramp which will be less than the total weight of the heavy box. Now, in sliding and rolling the weight of the heavy box along the ramp will be same but the difference will come in the type of the frictional force. Since, the rolling friction is less than the sliding friction. Hence, less force will be required when the box is rolled up an inclined plane on a cart.

Answer 2

The correct answer is:

B. Rolling the box up an inclined plane on a cart