T Transcripts
038 Unit 3, Pass me the wrench Exercise B
Listen and check. a. Can I have the spanner? b. Where’s the screwdriver? c. I need an Allen key. d. Pass me the wrench. e. What’s this called?
039 Unit 3, Pass me the wrench Exercise D
Listen and check. 1. A: The nut is loose! B: Tighten it.
2. A: The bolt is missing! B: Replace it.
3. A: The spanner is too small! B: Get a bigger one.
4. A: I can’t reach the nut! B: Use a box spanner.
5. A: This screwdriver is too big! B: Get a smaller one.
6. A: The nut is very tight! B: Loosen it with some oil.
7. A: The bolt is not long enough! B: Get a longer one.
8. A: Our spanners are the wrong size! B: Use an adjustable wrench.
040 Unit 3, The power of physics Exercise B
Listen to Part 1 of the radio programme. Good afternoon, everyone. My name is Professor Adamo Berrios and I’m here today to talk about a basic idea in engineering. A lot of engineering is based on one law of physics. We are going to look at examples of the law in practice. But let me start with a question. What’s the connection between a bottle opener, a flagpole and a ladder?
The connection is this: They are all simple machines. Machines? Maybe you think that all machines have engines or motors, but that isn’t true. Some machines have engines or motors. But listen to the definition of a machine. A machine turns mechanical energy into work. I’ll repeat that. A machine turns mechanical energy into work. So bottle openers, flagpoles and ladders are simple machines.
041 Unit 3, The power of physics Exercise C
Listen to Part 2. Let me explain. People have a lot of energy. They can use the energy to do work. They can open bottles. They can lift up a flag and wave it. And, of course, they can walk. But sometimes people don’t have enough energy. Maybe a bottle top is very tight or a flagpole is very high. In these cases, people need simple machines.
So how do simple machines work? They use a basic law of physics. Here it is: A small force times a large distance equals a large force. So think about the bottle opener, the flagpole and the ladder. How do these three items use the basic law?
042
Unit 3, The power of physics Pronunciation: Spelling ≠ sound
Listen, check and repeat. Distance. A small force times a large distance is a large force. Tight. The nut is too tight. Definition. What’s the definition of vehicle?
043 Unit 3, The power of physics Exercise F
Listen to Part 3. OK. We’re talking about simple machines. Let’s find out a bit about each type. The first type is the lever. A bottle opener is a lever. It has a long handle. Remember the basic law: A small force times a large distance equals a large force. The long handle provides the distance. A longer handle means you need a smaller force. There are many levers in engineering, for example, Allen keys and spanners.
Right. So that’s levers. Now, the second type is the pulley. A flagpole has a pulley. There is a rope and a wheel. The wheel is the pulley. The rope goes over the wheel. You pull one end of the rope and you can lift a heavy item on the other end. Large flags are very heavy, and you often have to lift them many metres above the ground. Actually, flagpoles have several pulleys. One pulley doesn’t help very much. More pulleys mean more rope which is more distance, so, again, you need a smaller force. There are many pulleys in engineering, such as cranes, and the gears on a bicycle. Cranes don’t use rope. They use metal cable. Bicycle gears use metal too, but the principle is the same.
OK. Finally, we have inclined planes. Plane doesn’t mean vehicle in the sky in this case. Plane means a surface, like the ground, or the floor of a building. Inclined means
204
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140 |
Page 141 |
Page 142 |
Page 143 |
Page 144 |
Page 145 |
Page 146 |
Page 147 |
Page 148 |
Page 149 |
Page 150 |
Page 151 |
Page 152 |
Page 153 |
Page 154 |
Page 155 |
Page 156 |
Page 157 |
Page 158 |
Page 159 |
Page 160 |
Page 161 |
Page 162 |
Page 163 |
Page 164 |
Page 165 |
Page 166 |
Page 167 |
Page 168 |
Page 169 |
Page 170 |
Page 171 |
Page 172 |
Page 173 |
Page 174 |
Page 175 |
Page 176 |
Page 177 |
Page 178 |
Page 179 |
Page 180 |
Page 181 |
Page 182 |
Page 183 |
Page 184 |
Page 185 |
Page 186 |
Page 187 |
Page 188 |
Page 189 |
Page 190 |
Page 191 |
Page 192 |
Page 193 |
Page 194 |
Page 195 |
Page 196 |
Page 197 |
Page 198 |
Page 199 |
Page 200 |
Page 201 |
Page 202 |
Page 203 |
Page 204 |
Page 205 |
Page 206 |
Page 207 |
Page 208 |
Page 209 |
Page 210 |
Page 211 |
Page 212 |
Page 213 |
Page 214 |
Page 215 |
Page 216 |
Page 217 |
Page 218 |
Page 219 |
Page 220 |
Page 221 |
Page 222 |
Page 223 |
Page 224 |
Page 225 |
Page 226 |
Page 227 |
Page 228 |
Page 229 |
Page 230 |
Page 231 |
Page 232 |
Page 233 |
Page 234 |
Page 235
