T A child sits on a toboggan and slides down a hill with a particular acceleration. If another child joins the first one on the toboggan, they will slide down the hill with the same acceleration. (When you create the free body diagram and then create an expression for the net force, you will find mass is in every term and will cancel.)
F If supporting cables of an elevator snapped and the elevator began falling, the passengers would become trapped against the ceiling of the elevator provided there is no air resistance or friction in the elevator shaft. (They would be in free fall and weightless because the elevator would also be in in free fall. They would not however be trapped.)
T Two people pushing an object across a frictionless surface will result in twice the acceleration than if only one person pushes. Assume the object slides in both cases and that both people push with the same force. (Since F=ma, they would have twice the acceleration since the force doubles but the mass remains the same)
T For two given surfaces, the coefficient of static friction is greater than the coefficient of kinetic friction. (Generally true as it is always harder to start an object in motion than to maintain motion, According to some tables I have in textbooks, it looks as if Teflon has equal coefficients)
T The sum of all the forces acting on a stationary object is the same as that acting on an object in uniform motion. (Newton's First Law)
