00:01
All right, so let's say we have a piston in a motor, and it can be kind of approximated like this.
00:08
And we're told that it has a mass 0 .45 kilograms, and it's operating at an angular frequency of 4 ,500 revolutions per minute, and it has an amplitude of 0 .05 meters.
00:28
So we want to know what's the equation of motion for the piston.
00:33
So we'll write at x of t.
00:35
This is going to be a cosine omega -t.
00:39
So this is going to be 0 .05 meters times the cosine.
00:44
Now we can write this as about 471 radiance per second.
00:49
So this is the cosine of 471t.
00:53
And then we want to calculate the acceleration of the piston at the end of its stroke.
00:57
So the acceleration is just going to be the angular frequency times the amplitude...