WEBVTT 00:00:00.000 --> 00:00:03.140 This is College Physics Answers with Shaun Dychko. 00:00:03.200 --> 00:00:06.340 We need to find the pressure in this hydraulic break system. 00:00:06.400 --> 00:00:08.740 So we can find the pressure anywhere... 00:00:08.740 --> 00:00:11.540 you know, in the slave cylinders or in the master cylinder 00:00:11.540 --> 00:00:12.900 because the pressure is the same throughout— 00:00:12.900 --> 00:00:14.980 that's what Pascal's principle says— 00:00:15.040 --> 00:00:18.400 and so we'll consider the pressure created by the master cylinder 00:00:18.420 --> 00:00:20.120 because we have information about it. 00:00:20.200 --> 00:00:24.400 We know that 500 newtons ends up being applied to this master cylinder 00:00:24.460 --> 00:00:28.540 and the diameter is 0.500 centimeters 00:00:28.540 --> 00:00:32.420 which we convert to meters by noticing that the prefix 00:00:32.420 --> 00:00:35.520 'centa' means times 10 to the minus 2. 00:00:35.980 --> 00:00:38.500 So pressure is force divided by that area 00:00:38.500 --> 00:00:41.680 and it's a circular cross-section here— 00:00:41.680 --> 00:00:43.260 this cylinder is circular— 00:00:43.260 --> 00:00:45.680 and so the area is π times its radius squared 00:00:45.720 --> 00:00:48.400 and its radius is half its diameter so I have written 00:00:48.400 --> 00:00:50.800 d over 2 here and squared 00:00:50.880 --> 00:00:55.780 and then this works out to 4 times the force divided by π times the diameter squared. 00:00:56.200 --> 00:00:59.520 That's 4 times 500 newtons divided by π times 00:00:59.520 --> 00:01:01.720 0.500 times 10 to the minus 2 meters squared 00:01:01.720 --> 00:01:05.260 which is 2.5 times 10 to the 7 pascals.