Fall Review Part A Key

Fall final review Answer Section COMPLETION 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20.

21. 22. 23. 24. 25. 26. 27. 28. 29.

ANS: seconds ANS: distance ANS: speed ANS: independent ANS: instantaneous ANS: acceleration ANS: kilogram kg ANS: unit ANS: controlled experiment ANS: scientific method ANS: line graph ANS: technology ANS: chemistry ANS: physical science ANS: responding variable ANS: scientific law ANS: scientific theory theory ANS: scientific model model ANS: safety rules safety procedures ANS: scientific model model ANS: 3.0 × 107 ANS: 14 ANS: Accuracy ANS: 293 ANS: direct proportion ANS: significant figures ANS: distance length ANS: vectors ANS: meters per second

30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 67. 68.

ANS: average speed ANS: direction ANS: direction ANS: vector addition ANS: speed velocity ANS: positive ANS: work ANS: output, input ANS: efficiency ANS: distance ANS: power ANS: energy ANS: force ANS: weight ANS: net force ANS: balanced forces balanced ANS: friction ANS: greater larger ANS: air resistance drag ANS: zero ANS: air resistance ANS: projectile ANS: inertia ANS: inertia, forward ANS: force, mass ANS: weight ANS: bowling ANS: wall ANS: equals ANS: two ANS: gravity ANS: direction ANS: move ANS: work ANS: joule ANS: motion ANS: power ANS: watt ANS: power

69. 70. 71. 72. 73. 74. 75. 76. 77. 78. 79. 80. 81. 82. 83. 84. 85. 86. 87. 88. 89. 90. 91. 92. 93. 94. 95. 96. 97. 98. 99. 100. 101. 102. 103. 104. 105.

ANS: force ANS: machine ANS: input ANS: increase ANS: mechanical advantage ANS: less ANS: screw ANS: first ANS: second ANS: less ANS: decreases ANS: compound ANS: lever ANS: work ANS: joule ANS: mass ANS: speed ANS: potential ANS: elastic ANS: PE = mgh ANS: chemical ANS: mechanical ANS: potential ANS: kinetic mechanical ANS: conversion ANS: conservation of energy ANS: 0 joules ANS: E ANS: light ANS: nonrenewable ANS: kelvins, degrees Celsius ANS: temperature ANS: greater ANS: from, to ANS: equal the same ANS: conduction ANS: conductor

MATCHING 106. ANS: B 107. ANS: C

108. ANS: D 109. ANS: A 110. ANS: A 111. 112. 113. 114. 115.

ANS: ANS: ANS: ANS: ANS:

E C A D B

116. 117. 118. 119. 120.

ANS: ANS: ANS: ANS: ANS:

C B E A F

121. 122. 123. 124. 125.

ANS: ANS: ANS: ANS: ANS:

D E C F B

126. 127. 128. 129. 130.

ANS: ANS: ANS: ANS: ANS:

D B F A C

131. 132. 133. 134. 135.

ANS: ANS: ANS: ANS: ANS:

D A E B F

SHORT ANSWER 136. ANS:

You would not use any fertilizer in your control set-up, but you have to use it in the experimental set-up, because you are trying to determine how the fertilizer affects the growth of tomato plants. The fertilizer is the experimental variable. 137. ANS:

The passengers will remain at rest relative to the train car, and since the train is rapidly accelerating, they will feel as if they are being pushed into the backs of their seats. Newton's first law applies to this situation, because the passengers at rest remain at rest. 138. ANS:

The horseshoe would weigh less. Weight is a measure of the pulling force of gravity, and since the gravity exerted by the moon on the horseshoe is less (by 1/6th) than the gravity exerted by the Earth on the horseshoe, the horseshoe would actually weigh less on the moon. 139. ANS:

The mass of the horseshoe would be the same. Mass is a measure of the amount of matter in an object, and the amount of matter in the horseshoe does not change when it is taken from one place to another. 140. ANS: Always follow your teachers instructions and textbook directions exactly. 141. ANS: to communicate with other scientists about the results of their investigations 142. ANS: a process in which scientists examine other scientists’ work 143. ANS: Earth and space science, life science, and physical science 144. ANS: a proposed answer to a question 145. ANS: a well-tested explanation for a set of observations or results 146. ANS: to help understand things that are too difficult to observe directly 147. ANS: larger 148. ANS: three 149. ANS: 32°F, 0°C, and 273 K 150. ANS: Science is a system of knowledge, while technology is the practical application of that knowledge to the solving of problems. 151. ANS: a bar graph 152. ANS: an inverse proportion 153. ANS: life science and Earth and space science 154. ANS: The universe is very old (about 13.7 billion years old) and very large (7.0 × 1026 meters in diameter). 155. ANS:

Answers may vary. Correct answers include: first class: seesaw, pliers, scissors, can opener (punches hole in can top) second class: door, wheel barrow, book cover, bottle cap remover third class: arms or legs of the human body, fishing pole, hammer to pound nails, baseball bat 156. ANS:

work = force × distance work = 50 newtons × 5 meters work = 250 newton-meters or 250 joules 157. ANS:

a. b. c. d.

joule (also newton-meter or watt-sec) joule (or newton-meter) newton watt

158. ANS:

a. The same b. The same 159. ANS:

Answers may vary. Correct answers include: a. heat from the sun b. electrical from a generator c. chemical from a battery d. nuclear from splitting atoms at a power plant e. light from a fluorescent bulb 160. ANS: The swimmer that swims faster develops more power only if both swimmers do the same amount of work. 161. ANS: Heat flows spontaneously from hot objects to cold objects. 162. ANS:

Frequency and period are inversely related. 163. ANS:

A and C 164. ANS:

0.5 seconds 165. ANS:

30 centimeters 166. ANS:

velocity = frequency × wavelength or velocity = wavelength ÷ period 167. ANS:

b 168. ANS:

destructive interference or They cancel each other out. PROBLEM 169. ANS:

You would be more likely to win the race at a speed of 6 miles per hour, because it is a faster speed than 8 kilometers per hour. 1 kilometer = 0.62 mile 10 kilometers = 6.2 miles If you ran at 6.2 miles per hour, it would take about one hour to complete 10 km. If you ran at 8 kilometers per hour, you would have run only 8 kilometers after one hour, and would still have 2 kilometers to go before reaching the finish line. 170. ANS:

speed = distance ÷ time speed = 13. kilometers ÷ 2.0 hours speed = 6.5 km/h 171. ANS:

4.00 minutes = 4.00 minutes × 60.0 seconds 4.00 minutes = 240. seconds speed = distance ÷ time speed = 1500. meters ÷ 240. seconds speed = 6.25 m/sec 172. ANS:

speed = distance ÷ time speed = 60 meters ÷ 0.8 seconds speed = 75 meters per second 173. ANS:

total distance = (first speed × 3 hours) + (second speed × 1 hour) total distance = (10 miles per hour × 3 hours) + (20 miles per hour × 1 hour) total distance = 30 miles + 20 miles = 50 miles total time = five hour period = 5 hours average speed = total distance ÷ total time average speed = 50 miles ÷ 5 hours average speed = 10 miles per hour 174. ANS:

weight in newtons = weight in pounds ÷ 0.228 pounds per newton weight in newtons = 5.00 pounds ÷ 0.228 pounds per newton weight in newtons = 21.9 newtons 175. ANS:

weight in newtons = mass × acceleration of gravity weight in newtons = 5.0 kilograms × 9.8 m/sec2 weight in newtons = 49 newtons 176. ANS:

force required = weight of object ÷ number of supporting ropes force required = 250 newtons ÷ 5 ropes force required = 50 newtons 177. ANS:

input arm length × input force = output arm length × output force (input arm length × input force) ÷ output force = output arm length

(6.0 feet × 125 pounds) ÷ 500 pounds = output arm length output arm length = 1.5 feet 178. ANS:

a.

b.

c.

work input = force × distance work input = 250 newtons × 50 meters work input = 12,500 joules work output = force × distance work output = 2,400 newtons × 4 meters work output = 9,600 joules efficiency = work output ÷ work input × 100% efficiency = (9,600 joules ÷ 12,500 joules) × 100% efficiency = 77%

179. ANS:

Judy does more work. She does 2,400 joules of work. work = force × distance work = 600 N × 4.00 m work = 2,400 J Jennifer does only 1,800 joules of work work = force × distance work = 450 N × 4.00 m work = 1800 J The girls generate the same amount of power: power = work ÷ time For Judy, power = 2,400 J ÷ 4.0 sec power = 600 watts For Jennifer, power = 1,800 J ÷ 3.0 sec power = 600 watts 180. ANS:

Dad is wrong! It is sixteen times as dangerous. Increasing speed from 20 to 80 mph (quadrupling the speed) increases the kinetic energy by 16 times. Ek = 1/2mv2 181. ANS:

182. ANS:

183. ANS:

184. ANS:

185. ANS:

186. ANS:

187. ANS: 188. ANS: = 10 J decreased by 10 J 189. ANS:

190. ANS:

velocity = wavelength ÷ period velocity = 2.0 m ÷ 5 sec velocity = 0.4 m/sec ESSAY 191. ANS: The steel ball started out slowly. Then it continued to speed up throughout the experiment. 192. ANS:

193.

194. 195.

196.

A scientific law is a statement that summarizes a pattern found in nature, without attempting to explain it. A scientific theory explains the pattern. ANS: Possible answers: The universe is very large and very old. A small amount of the universe is matter. Matter on Earth usually is either a solid, liquid, or gas. All matter is made of atoms. Forces cause changes in motion. Energy can be transferred from one form or object to another, but it can never be destroyed. ANS: Possible answer: 1) make observations, 2) ask questions, 3) develop a hypothesis, 4) test the hypothesis, 5) analyze data, 6) draw conclusions, 7) revise hypothesis. ANS: In peer reviews, scientists review and question other scientists’ data. Scientists also help determine if the data is accurately reported. If the review finds errors in the data, in the conclusions, or in the experimental procedures, the hypothesis may need to be revised. ANS:

a. Reflection occurs as a wave meets a boundary and bounces off, traveling in a new direction. b. Refraction occurs as a wave passes through a boundary. It may change wave direction. c. Diffraction occurs when a wave travels around an obstacle or through an opening in a boundary. Wave direction is usually changed. d. Absorption occurs as the amplitude of the wave decreases when the wave passes into and through a material. OTHER 197. ANS:

The length of the object is 2.60 cm. (Note: The centimeter scale is marked off in millimeters, so you can read to the nearest 0.5 mm, or 0.05 centimeter.) 198. ANS:

A = inverse, B = strong, C = none, D = weak 199. ANS:

a. b. c. d. e.

NO YES YES YES NO

200. ANS:

The line should be drawn horizontally at a speed of 6.0 meters/second 201. ANS:

a. b. c. d. e.

3rd 1st 3rd 2nd 1st

202. ANS: 8.8 g/cm3

203. ANS: mass 204. ANS: a direct proportion 205. ANS: the density of the fluid 206. ANS: g/cm3 207. ANS: monthly precipitation in centimeters 208. ANS: December 209. ANS: The precipitation data might provide insight into agriculture growth trends. 210. ANS: approximately 165 cm 211. ANS: about 18 cm, which equals 0.18 meters 212. ANS: Graph A shows periods of constant speed (0–8 s, 8–12 s, 12–20 s). 213. ANS: The object moves at constant speed for 8 seconds, is at rest for the next 4 seconds, and then moves at constant speed for the next 8 seconds. 214. ANS: Graph B shows acceleration. The upward slope of the line indicates that an increasing distance is covered each second. 215. ANS: The object moved a distance of 300 m in 8 s. The object’s average speed is 37.5 m/s. 216. ANS: Graph A; the slope is steeper. 217. ANS:

a. fulcrum at the wheel, output force at the load, input force at the handle b. second class c. the load/output force is located between the fulcrum and input force 218. ANS: 0 kg m/s 219. ANS: The momentums of both skaters are equal in size but opposite in direction. 220. ANS: The push on Skater B by Skater A accelerates Skater B forward. 221. ANS: According to Newton’s third law of motion, as Skater A pushes on Skater B, an equal and opposite force pushes back on Skater A. The unbalanced force causes Skater B to accelerate backward. 222. ANS: No; Skater A is exerting the same force on Skater B as before and so Skater B is exerting the same force on Skater A as before. The result is that Skater’s A motion will be the same. 223. ANS:

Ideal mechanical advantage =

3

224. ANS: The ramp’s AMA would increase. 225. ANS: Its efficiency would increase; friction would decrease. 226. ANS: an inclined plane 227. ANS: It is less. 228. ANS: 1.0 m 229. ANS: wheel and axle 230. ANS: C 231. ANS: The gravitational potential energy of the ball is the same at both locations; the height is the same. 232. ANS: No; since the ball is always moving to the right between locations A and F, at every point between A and F, the ball has kinetic energy. Because the ball has kinetic energy at each point, it has some mechanical energy at each point.