Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

Consider the following three cases. You try to push on a large box that has a ma

ID: 1536053 • Letter: C

Question

Consider the following three cases. You try to push on a large box that has a mass equal to your mass across the floor. However, the box does not move due to friction. How do the magnitudes of the forces between you and the box compare to each other? You switch to a box that has a mass that is half of your mass and try to push it across the floor, but it also does not move. How do the magnitudes of the forces between you and the box compare to each other? You are able to place the box that has a mass half of your own onto a platform with wheels and you are able to push the box across the floor. How do the magnitudes of the forces between you and the box compare to each other?

Explanation / Answer

a)

By Newton’s 2nd law,

Fnet = ma

Fnet is addition of all forces acting on the box and ‘a’ is its acceleration = 0 m/s^2 since it is not moving

   Fyou – Ffriction = 0

Thus,

   Fyou = Ffriction

b)

By Newton’s 2nd law,

Fnet = ma

Fnet is addition of all forces acting on the box and ‘a’ is its acceleration = + value m/s^2 since it is moving

   Fyou – Fbo = 0

Thus,

   Fyou = Fbox

c)

By Newton’s 2nd law,

Fnet = ma

Fnet is addition of all forces acting on the box and ‘a’ is its acceleration = 0 m/s^2 since it is not moving

   Fyou – Fbox= positive value

Thus,

   Fyou > Fbox