Does frictional force increase or decrease based on velocity?

Explanation:

Many would know it as a reaction force. Reaction force is the force by the surface on the object perpendicular to it's motion. So if we apply force on the sliding block perpendicular to it's direction of motion, friction will increase. ... That force is proportional to the velocity with which it is moving.

less than one you can't create energy

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2