UNIT 2 REVIEW au Knowledge/Understanding cm Thinking/Investigation Communication & Application Knowledge 7. The slope of a net force versus acceleration diagram For each question, select the best answer from the four represents which of the following? (3.3) a alternatives. (a) velocity 1. Which of the following is the SI unit of force? (3.1) zu (b) mass (c) weight (a) kg (b) N (d) time (c) m/s' 8. Which of the following scientists explored areas (d) km/h such as the nature of gravity and black holes, and showed that even black holes can lose mass through 2. The force exerted on an object by pulling on an radiation? (3.6) Ru attached rope or string is called (a) Galileo (a) tension (b) Newton (b) friction (c) Einstein (c) normal (d) Hawking (d) gravity (3.1) RIM 9. Falling objects will stop accelerating at the point at 3. You push a box across a floor in the direction which the force of the air resistance is equal to that of E 40" N. In which direction is the friction force gravity. The speed they reach is called the acting? (3.1) BY (a) resultant speed (a) W 40's (b) final speed (b) N 50' E (c) terminal speed (c) N 40 E (d) fall speed (4.1) (d) W 50' s 10. An object in free fall has which of the following forces 4. Which of the following best describes the normal solely acting on it? (4.1) Du force that acts on an object? (3.1) a) gravity (a) a force that resists the motion or attempted b) electromagnetic motion of an object in contact with a surface (c) friction (b) a perpendicular force exerted by a surface on an object in contact with the surface (d) strong (c) the force in the nucleus of atoms that holds 11. An object has a smaller cross-sectional area than protons and neutrons together another object of similar mass. How will this affect (d) the force between positively and negatively the air resistance it experiences? (4.1) Du charged objects (a) The object will experience more air resistance. 5. The force involved when protons and neutrons (b) The object will experience the same amount of air transform into other particles is the resistance. (a) weak nuclear force (c) The object will experience less air resistance. (b) strong nuclear force (d) The object will experience negative air resistance. (c) gravitational force 12. Which of the following terms is used to describe the (d) electromagnetic force (3.1) zu force exerted by a surface on a stationary object that prevents it from moving? (4.2) am 6. The G-suit and other space suit technologies are (a) static friction designed to do which of the following to help counteract the effects of Newton's first law? (3.2) Du (b) kinetic friction (a) prevent inertia from causing blood to move into (c) coefficient of friction the legs by applying pressure to the legs (d) normal friction (b) prevent the effects of gravity on the body (c) use electromagnetic signals to counteract the effects of solar radiation on the wearers (d) provide the wearers with hydraulic stabilizers so that they can maintain their balance on the Moon13. Why does steel on ice have such a small coefficient of Match each term on the left with the most appropriate kinetic friction when ice is slightly colder than 0 "C? description on the right. (4.5) KIM (a) A thin layer of slushy water exists on the surface 25. (a) dynamics (i) the force caused by the charge of particles of ice. (b) The steel is able to melt the ice when it is moving. (b) normal force (ii) a perpendicular force (c) Steel has a repelling property when it gets close exerted by a surface to ice. (c) force field (iii) the area of a car that (d) When steel gets cold, its surface gets smoother. is meant to be crushed during a collision Indicate whether each statement is true or false. If you think (d) coefficient of (iv) an area of physics that the statement is false, rewrite it to make it true. kinetic friction explains why objects 14. Friction is a force that acts to maintain the motion of move the way they do an object. (3.1) u (e) electromagnetic (v) represents the ratio of 15. In the nucleus of an atom, the gravitational force force kinetic friction to the holds together the protons and neutrons. (3.1) normal force 16. Gravity is the only fundamental force that does not (f) crumple zones (vi) a region of space have an attraction effect. (3.1) zu surrounding an object 17. Seat belts use Newton's first law by having an inertial that can exert a force on pendulum that locks the seat belt in place when the other objects (3.1, 4.1, car suddenly brakes. (3.2) zu 4.2, 4.4) BY 18. A force of 10 N that acts on a box with a mass of Write a short answer to each question. 2.5 kg will accelerate it at a rate of 4 m/s' even if there is also a friction force acting on the box. (3.3) Gam 26. Place the following objects in order from having the 19. Steven Hawking considers Einstein to be the greatest least amount of inertia to having the most amount figure in mathematical physics and the Principia his of inertia: atom, pencil, baseball, car, hockey player, greatest work. (3.6) Gu proton, motorcycle. (3.2) zu 20. Air resistance acts opposite to the direction of motion 27. Place the following combinations of materials in if there is no wind. (4.1) zu order from having the least amount of kinetic friction to having the most amount of kinetic friction: wood 21. On the Moon, both your mass and your weight will on dry snow, Teflon on Teflon, rubber on concrete, decrease. (4.1) Bu ice on ice. (4.2) RIM 22. For a flat surface, the static frictional force can be determined by multiplying the coefficient of static Understanding friction by the mass of an object. (4.2) zu 28. Draw a free-body diagram for each situation. (3.1) zu 23. The static friction from the ground enables you to (a) A skydiver has reached terminal speed in push off with one foot and accelerate your body in free fall. motion. (4.3) BY (b) A boy pushes horizontally and accelerates a box 24. Quebec law requires that drivers must put snow across a rough floor. tires on their vehicles from November 15 to April 15. (4.6) QU 29. Describe in your own words the difference between a system diagram and a free-body diagram. Explain how each is used. (3.1) Bu 30. The following situations describe a student moving a box: (3.1) (a) A student pulls a large box across a smooth floor to the right. Draw the free-body diagram. (b) A student pushes a large box across a smooth floor to the right. Draw the free-body diagram. (c) Are there any differences between the diagrams in (a) and (b)? Explain