00:01
So here, for part a, we're going to apply newton's law to the y -axis.
00:06
Of course, in the y -axis, there is no acceleration.
00:08
So we can say force normal plus f -sign of theta minus m -g would equal zero.
00:17
We can then say that in the x direction, f -cosine of theta, minus the force of static friction would equal the mass times the acceleration.
00:32
In this case, we can say that the force normal is going to be equal to mg minus the force applied sign of theta.
00:41
Therefore, here we can say that this is going to equal zero because there isn't any acceleration in the x direction either.
00:50
We can say that f cosine of theta minus the coefficient of static friction multiplied by mg minus f sine of theta would equal zero.
01:04
We know that here theta equals 42 degrees, and we know the coefficient of static friction equals 0 .42.
01:14
So we can say that if we wanted to obtain f, f cosine of 42 degrees minus 0 .42 times mg.
01:26
Mg equals the weight, and the weight in this case would equal 180 newtons minus f sign of of 42 degrees, this is equaling 0.
01:41
Solving for f, we find that f is equaling 74 newton's.
01:46
This would be our answer for part a...
