13. A sofa has mass 32kg and the coefficient of kinetic friction between the crate and floor is 0.57 What force must you push on a sofa to accelerate it at 1.8m/s/s across a rough floor?

Avector of magnitude 2 cannot be added to a vector of magnitude 3 so that the magnitude of the resultant is a. zero b. 1 c. 3 d. 5 e. 7

Which statement is the best definition of an atom? a) anything that has mass and occupies space. b) the smallest particle that has the properties of an element. c) a substance that cannot be broken down chemically into simpler substances. eliminate d) the smallest unit of a substance that exhibits all of the properties characteristic of that substance.

The ability to make things happen is also called a. heat b. force c. matter d. energy