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Rutgers, The State University of New Jersey

University of Washington

Simon Fraser University

03:38

Keshav S.

(II) A person has a reasonable chance of surviving an automobile crash if the deceleration is no more than 30 $g$'s. Calculate the force on a 65-kg person accelerating at this rate.What distance is traveled if brought to rest at this rate from 95 km/h?

01:24

(II) According to a simplified model of a mammalian heart, at each pulse approximately 20 $g$ of blood is accelerated from 0.25 m/s to 0.35 m/s during a period of 0.10 s. What is the magnitude of the force exerted by the heart muscle?

03:04

Kai C.

(I) A 7150-kg railroad car travels alone on a level frictionless track with a constant speed of 15.0 m/s. A 3350-kg load, initially at rest, is dropped onto the car. What will be the car's new speed?

04:15

Kathleen T.

Create your own quiz or take a quiz that has been automatically generated based on what you have been learning. Expose yourself to new questions and test your abilities with different levels of difficulty.

Create your own quiz

welcome to our first example video. Looking at the Doppler effect in this video, we're going to consider a train coming into the station and you're standing at the station. No motion here. So speed of the observer is 0 m per second. We'll say that the train is coming in with a speed. So this is the speed of source is equal to 5 m per second, and it sounds a horn or whistle, whatever it iss. Okay, so you have sound. It propagates out because it's moving forward. Remember, the picture of the sound waves is actually going to look more like this with ex squished in this direction towards you and extended out in the direction behind it. Okay, let's say that the frequency of the whistle is equal to 600 hertz and so we want to know what's the frequency that we actually here? Okay, we know frequency of the observer is equal to frequency of the source multiplied by speed of sound, plus or minus B not divided by speed of sound, plus or minus B source. Okay, well, V, not zero. So that goes away. Speed of sources. 5 m per second. It's moving towards you, which means that F not should be greater NFS. In order for that to happen, this ratio must be greater than one. Which means we want the denominator to be small. So we're going to subtract. So we have f not. It's equal to F s times Bs divided by V s minus V source and we're done. Remember that speed of sound at room temperature is approximately 343 m per second. So unless told otherwise, you can generally use that number.

Superposition

Thermal Properties of Matter

The First Law of Thermodynamics

Kinetic Theory Of Gases

The Second Law of Thermodynamics

02:12

02:35

04:09