Force and Motion Student Test

Transcription

1 Force and Moion Suden Tes 8 h Grade Par I: Muliple Choice Choose one correc answer for each of he following quesions. 1. You are waching he fligh of a small, remoe-conrol model airplane as i flies in a haphazard pah oer an empy fooball field. Which of he following saemens abou he moion of he plane is correc? a. When he plane flies hrough he poin from which i sared, he disance he plane has raeled is zero. b. When he plane flies hrough he poin from which i sared, he change in posiion for he plane is wice he disance raeled. c. The disance raeled by he plane can be a posiie or a negaie number. d. The disance raeled by he plane can only be a posiie number. 2. Saring a a flagpole, you begin walking due Eas wih equal srides for 200 srides. Then you reerse direcion and walk 100 srides direcly back oward he flagpole. Now wha is your posiion? a. 100 srides b. 100 srides Eas of he flagpole c. 300 srides d. 300 srides Eas of he flagpole 3. An objec moing wih consan elociy mus moe in a 1 a. sraigh pah and experience larger and larger changes in posiion during each successie second. b. cured pah and experience larger and larger changes in posiion during each successie second. c. sraigh pah and experience equal changes in posiion during each successie second. d. cured pah and experience equal changes in posiion during each successie second.

2 Figure 1: Velociy ersus Time Graphs for Two Trains Moing in Sraigh Lines A B 0 4. Which of he following is rue abou he moion of he rains? (Assume ha boh rains are moing in sraigh lines.) a. Boh rains are moing wih a consan elociy. b. Train A is moing wih a consan elociy while he elociy of rain B is increasing wih ime. c. Boh rains hae elociies ha are increasing wih ime. d. Train B is moing wih a consan elociy while he elociy of rain A is increasing wih ime. 5. Choose he correc saemen abou he posiion ersus ime graphs ha would correspond o he elociy ersus ime graphs in Figure 1 aboe. a. The posiion ersus ime graph associaed wih graph A mus be curing while he posiion ersus ime graph associaed wih graph B mus be a sraigh line. b. The posiion ersus ime graph associaed wih graph B mus be curing while he posiion ersus ime graph associaed wih graph A mus be a sraigh line. c. The posiion ersus ime graphs associaed wih boh graphs are curing. d. The posiion ersus ime graphs associaed wih boh graphs are sraigh lines. 2

3 6. Which of he following is NOT an objec experiencing acceleraion? a. An objec which moes in a sraigh pah and experiences equal changes in posiion during each successie second. b. An objec moing a consan speed around a corner. c. An objec which moes in a sraigh pah and experiences larger and larger changes in posiion during each successie second. d. An objec which moes in a sraigh pah and experiences smaller and smaller changes in posiion during each successie second. 7. A race car is raeling around an oal rack a a consan speed. A which poin on he oal rack does he race car accelerae? See Figure 2 below. a. The car acceleraes a poin A Figure 2: Race Track b. The car acceleraes a poin B A c. The car acceleraes a poin C d. The car neer acceleraes. B C Coninue o he nex page for #8. 3

4 A Figure 3: Timed Posiions Two balls, A and B, are moing as illusraed in he figure below. The numbers represen readings of a clock in seconds. A each clock reading he posiion occupied by each ball is represened by a large black do. A clock ime 1 ball A occupies he posiion marked 1, and ball B occupies he posiion marked 1, ec. The arrows indicae he direcion of moion of boh balls. Each line is 1 meer in oal lengh. A B Use Figure 3 o Answer # Which objec(s) is(are) acceleraing? a. only A b. only B c. boh A and B d. Neiher A nor B 9. Which objec(s) could hae only balanced forces acing on i (hem)? a. only A b. only B c. boh A and B d. neiher A nor B 10. The moion of which objec(s) would be represened by a cured line on a posiion ersus ime (x ersus ) plo? a. only A b. only B c. boh A and B d. neiher A nor B 4

5 Figure 4: Susan s Walk o School Susan opened her fron door and headed o school. She picked up speed as she lef her fron door and soon reached her usual moderae pace. Abou halfway o school she slowed o a sop and wached a bird building a nes. When she realized she was lae, she ran a a fas pace he res of he way o school o aoid being marked lae. She didn slow unil she was sopped by he safey guard in fron of he school. A. B. V C. D. 11. Which VELOCITY VERSUS TIME graph In Figure 4 aboe shows Susan s elociy during her walk o school? a. Graph A b. Graph B c. Graph C d. Graph D 5

6 12. For he siuaion described in Figure 4, we can conclude ha Susan a. did no accelerae while walking o school. b. acceleraed only once while walking o school. c. acceleraed wice while walking o school. d. acceleraed more han wice while walking o school. 13. Wha happens o he moion of an objec if he original ne force is ripled? a. he elociy of he objec is 3 imes wha is produced by he original ne force b. he acceleraion of he objec is 3 imes wha is produced by he original ne force c. he elociy of he objec is 1/3 of wha is produced by he original ne force d. he acceleraion of he objec is 1/3 of wha is produced by he original ne force 14. If acceleraion decreases while he force says he same hen he mass mus hae: a. increased. b. decreased. c. sayed he same. Use Figure 5 on he nex page o answer #15. 6

7 Figure 5: Rocke Car Imagine a car ha is equipped wih a rocke engine on a sraigh race rack. The rocke engine applies a large consan force ha moes he car forward. Assume ha he car moion is begun a ime () = 0 wih a posiion (x) = 0. The moion of he car can be described by a posiion ersus ime graph and a elociy ersus ime graph. a. x b. x c. x d. x 7

8 15. Which pair of graphs correcly describes he moion of he rocke car described in Figure 5? a. Pair a b. Pair b c. Pair c d. Pair d 16. The moon is araced o he Earh so we know ha he Earh is a. he Earh is repelled by he moon. b. he Earh is araced o he moon. c. he moon has no effec on Earh. 17. A friend is on a sled ha is on ery slippery ice (no fricion). You apply a force and he sled speeds up. Laer ha day wo of your friends ge on he sled. You push again making he sled speed up jus as you did before. More force is required o speed up he sled wih wo friends because: Three of he following saemens are TRUE. Which one is FALSE? a. here is more mass. b. here is more ineria. c. here is no fricion. d. here is more graiy. 17. In he siuaion picured below, suden A weighs 150 pounds and suden B weighs 100 pounds. Suden A gies suden B a push. Which of he following is rue abou he siuaion? a. Neiher suden exers a force on he oher. b. Each suden exers a force on he oher bu B exers he larger force. c. Each suden exers a force on each oher bu A exers he larger force. d. Each suden exers he same amoun of force on each oher. A B 8

9 Par II: Open Response 18. Horse jockeys mus wach heir weigh because here are resricions as o how much weigh a horse can carry in a race. For example, in he Kenucky Derby horses are resriced o carrying 126 pounds. Tha oal includes he weigh of he jockey and all he gear on he horse. If he jockey is oo ligh he officials will add weighs o he gear so ha all horses in he race are carrying he same weigh. a. Describe Newon's Second Law of Moion. b. Use Newon's Second Law of Moion o explain how increasing he weigh horse carries would impac is abiliy o win he Kenucky Derby. 9