00:01
A 600 kilogram car is going around the curve, the radius of 120 meters, but it is banked on the angle of 120 degrees, so 20 degrees rather, 20 degrees for the angle here.
00:16
I want to find, and the speed of the car is 205 per second, what is the minimum contraint of static friction required for the car not to skate.
00:23
Let's see the car is right here.
00:28
We have the weight of the car, mg.
00:31
We have normal force.
00:33
Perpendicular to the slope and we have the component of the which is pulling the car down the slope mg sign theta the component of the weights which is um perpendicular to the slope is mg cost theta um we have the centrifugal force which is equal to mv squared divided by r so we could have the friction on force and two in two situations, we could have the frictional force here or the frictional force here.
01:10
If we have this friction out of force going to the left, it would mean that the car has motion, the car will tend to skate in this direction because the friction of force will be opposing the motion.
01:20
So we need to find which force is greater.
01:24
The component of the centrifugal force in this direction or the component of the weight in this direction.
01:32
And we can find that out by calculating.
01:34
So using the triangle here is going to give us fc.
01:44
This angle is still 20 degrees.
01:47
This is going to be fc cost 20 degrees.
01:54
So mg, sign, theta minus fc cost 20, cost theta.
02:09
So the mass is 600 kilograms.
02:14
G's 9 .8 .1...