SPH3U Name: UNIT 4 PRACTICE TEST - FORCES Knowledge /10 Thinking /20 Application /25 Communication /5 Total /60 For full communication marks, show all of your work and be clear and organized in your solutions. Communication [5] MULTIPLE CHOICE [K5] 1. A child stomps his feet to remove snow from his boots. This fact illustrates Newton's: a. first law b. second law c. third law d. law of gravitation 2. An object, moving at constant velocity, must: a. have a net force acting on it. b. eventually stop due to the force of gravity. c. have all forces acting on it balance each other. d. not have a force of gravity acting on it. 3. The mass of an object: a. is numerically equal to its weight. b. has the same units as weight. c. depends on its location. d. is a measure of its inertia. 4. A child is standing on the floor. If the action force is the force of gravity of Earth pulling down on the child, then the reaction force is: a. the force of the floor pushing up on the child. b. the force of gravity of the child pulling up on the Earth. c. the force of the child pushing down on the floor. d. a net force causing the child to accelerate. 5. Acceleration is always in the direction of the: a. net force b. initial velocity c. final velocity d. displacement
TRUE/FALSE If false, correct the italicized word. [K5] 1. Objects dropped at the equator will fall with greater acceleration than if dropped at one of the poles. 2. An elevator moves vertically upward with a constant speed. The vector sum of all the forces acting on the elevator is precisely zero. 3. The reason your head feels like it jerks backward when pulling away from a stop sign is best explained by Newton's First Law. 4. An airplane is flying in level flight with constant velocity. The forward thrust force acting on the airplane is greater than the drag force acting in the opposite direction. 5. A gravitational force is a perpendicular force on an object exerted by the surface with which it is in contact. SHORT ANSWER 1. Draw a FBD for each underlined object. Use an arrow (like done in class) to indicate the object's direction of motion (if any). In each case be sure to (i) label the force(s) appropriately and (ii) indicate those forces that are equal. [A6] a. A ball is rising vertically against air resistance. b. A person is standing in an elevator that is moving upward at a constant speed. c. A crate is being dragged along a floor by a rope that is horizontal.
2. A person exerts a constant force of 1.5 N to pull a 2.0 kg object at constant velocity along a level surface on the moon (g = 1.6 N/kg [down]). What is the coefficient of kinetic friction? [A5] 3. A 60 kg skydiver is falling through the air