While the cart is moving along an aisle, it comes in contact with a smear of margarine that had recently been dropped on the floor. suddenly the friction force is reduced for -40.0 newtons to -20.0 newtons. what is the net force on the cart if the "pushing force" remains at 40.0 newtons? does the grocery cart move at constant velocity over the spilled maragine?

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.