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_.P E R|OD DATE NA ME CH APTER: 5 E, valuation FORCES A. TestingConcepts ln the space to the left, write the letter of the answer to each question. 1. - The attractiveforce that acts between all objects is a. electromagneticforce b. gravitationalforce c. strongnuclearforce d. weak nuclearforce. 2. - The strongestforce is a. electromagneticforce c. strongnuclearforce b. gravitationalforce d. weak nuclearforce. 3. - Metalssuch as copper can be pounded into thin sheetsdue to a. electromagneticforce b. gravitationalforce c. strongnuclearforce d. weak nuclearforce. 4. - According to NeMon's law, an object with no net force acting on it remains at rest or in motion with a constantvelocity. a. first b. second c. third 5. - NeMon's law statesthat the accelerationof a body is directly proportional to the net force on it and inverselyproportionalto its mass. a. first b. second c. third 6. - Losingspeedas you ride your bike uphill demonstrates Newton'sa. first b. second c. third 7. - Two teams in a tug of war exeft the sameamount of force on each other and the rope does not move. Newton's_ law explainswhy the rope does not move. a. first b. second c. third B. - lf you push againsta wall, the wall pushesback againstyou with a. no b. less c. equal d. more 9. - The gravitationalforce exerted by a large body, such as Earth,is a. weight b. mass c. acceleration d. inertialmass. 10. - Mass and weight are related by a. the force of gravity b. newtons c. friction law. force. d. none of these. 1'1.- Difficulty in pushing a large crate from rest involves a. gravity b. sliding friction c. staticfriction d. balancedforces. 12. - When the drag force on an object equals the force of graviry,occurs. a. acceleration b. inertialmass c. terminalvelocitv d. maximum mass 13. - The effect of air resistanceon the tail of a kite is body of the kite. a. the same as b. lessthan c. more than 14. - lf the force of gravityon a balloon is 3000 N, and the lift force provided by the atmosphere is 3300 N, in which directionis the net force acting? a. upward b. downward c. toward the east d. There is no net force. the effect of air resistanceon the EVALUATION15 CHAPTER NAME 5 Evaluation B. ApplyingConcepts Answer the following questions in two or three complete sentences. 1. Explainthe relationshipbetweenmassand weight on Earth.Would this relationshipchangeon Mars? Explainyour answer. 2. Why is it easierto stopa compactcar than a largestationwagonwhen both are movingat the samespeed? 3. An elevatoris travelingfrom the lobbyto the top of the building.As it stopson the top floor, in which directionis its acceleration? Exolain. 4. In the drawingat right,usearrowsto showthe two horizontaland two vertical forcesactingon the boat as it is pulledto the shore.lstherea netforce on the boat? 5. Explainthe difference betweenactionreactionforcesand netforces.Usingthe boat shownin the figure,describean exampleof each. 6. Whatisthe relationship betweenslidingfrictionandspeed? Between slidingfrictionand normalforce? 7. Supposeyou try to pull a rope tied to a largecarton.You cannotmove the carton.What forces are actingon your hand? 16 E V A LUA T I ON : CHAPTER : F. \: I -/ NAME Evaluation C. Understanding Concepts 1. What force is requiredto accelerate a 6.0-kgbowlingball at +2.0 mls2? 2. What is the massof a cat that weighs30.0 N? 3. Accelerationdue to gravity on Mars is 3.8 m/s2. a. Would a 5.0-kg watermelon weigh more on Earth or on Mars? b. How would the massof the watermelondiffer? 4. What is the inertialmassof a 75-Ndog? 5. How much forceis neededto keepa 7}-kgbox movingat a constantvelocityacrossa warehouse floor if the coefficientof frictionbetweenthe box and the floor is 0.21? 6. A 597-Ncross-country skieris movingover packedsnow.The coefficientof frictionbetweenthe skisand the snow is 0.11.What force is requiredto keepthe skiermovingat a constantspeed? 7. What is the coefficient of frictionbetweena 65-kgrollerskaterand the floor of the rollerrink if the skatermovesat a constantspeedwith a force of z5 N? E V A LUATI O N 17 C HAPTER NAME 5 Evaluation D. ExtendingConcepts 1. An elevatorhasa massof 1.10 x 103kg. Supposeit accelerates upwardat 0.45 m/s2.What is the force actingon the elevator'ssupportcable? 2. A rocketweighs2.O x 10i N. lts enginesexert +25 x 106N of force at lift-off. a. What is the massof the rocket? b. What is its accelerationwhen it liftsoff? c. The averageacceleration of the rocketduringits 7.0 minutelaunchis 10.0m/s2.What velocity does it reach? 3. A 47-N box is pulledalonga horizontalsurfaceby a 25-Nweighthangingfrom a cord alonga frictionlesspulley. a. What is the acceleration of the box and the weight? b. What force is exertedon the cord? 18 EVALUATION