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Rank in order, from largest to smallest, the sizes of the friction forces `vec(f)_(a)` to `vec(f)_(c)` in these `5` different situation. The box and the floor are made of the same materials in all situations.
`(a)`
`(b)`
`(c)`
`(d)`
`(e)`

A

`F_(d) lt F_(b) =F_(c) =F_(e) gt F_(a)`

B

`F_(c) lt F_(b) =F_(d) =F_(e) gt F_(a)`

C

`F_(b) =F_(c) =F_(d)=F_(e) gt F_(a)`

D

`F_(b) gt F_(c) =F_(d)=F_(e) gt F_(a)`

Text Solution

Verified by Experts

The correct Answer is:
4
`f_(b) gt f_(c)=f_(d) =f_(e) gt f_(a)`. Situations c, d and e are all kinetic friction, which does not depend on either velocity or acceleration. Kinetic friction is smaller than the maximum static friction that is exerted in b. `f_(a)-0` because no friction is needed to keep the object at rest.
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