Horizontal Circular Motion

Recap of Centripetal Acceleration Because the speed of an object displaying circular motion is constant and tangential, circular motion produces a centripetal acceleration (acceleration directed toward the center of the circular path.)

Recap of Centripetal Force Since acceleration is toward the center, so is the force that is produced from that acceleration This force is not always a separate force but can be made up of several forces. It is best to think of it as the net force required to hold the object on its circular path

Horizontal Circular Motion Frictional forces between the ground and objects allow “turns” to be made. That means that the net force as you round a corner is friction.

Example 1: Determine the maximum speed at which a 1700 kg truck can round a curve that has a radius of 20.0m, if the coefficient of friction between the tires and the road is 0.58.

Example 2 1. A car has a mass of 1400 kg and is going around a corner that has a radius of 100 m, the coefficient of friction between the car and the road is 0.650. What is the maximum force the car have going around the corner without sliding off the road? i. Force due to friction

ii. Find the maximum speed the car can go without sliding off the curve. Centripetal force must be less than 8927 N

Centrifugal Force the outwards force is sometimes referred to as centrifugal force since centrifugal force is an imaginary force, nothing causes it centrifugal force only exists because of Newton’s 3rd Law

Newton’s 3rd Law When you are pulling on the rope inward the ball is pulling on your hand outward Force A on B = - Force B on A

Misconceptions about Centripetal Force it is mistakenly thought that centripetal force pulls outward away from the centre of a circle so why when you swing a ball on the end of a rope does the ball pull outward away from your hand? Think: what causes the ball to continue moving in a circular path? What happens when you let go of the rope?

Eg) A centrifuge that simulates increased gravity rotates at 2800 rpm Eg) A centrifuge that simulates increased gravity rotates at 2800 rpm. The measure of the radius of the spinning drum is 2.5 cm. Determine centripetal acceleration.

Space stations are circular and rotate to generate an acceleration due to gravity equal to centripetal acceleration of 9.81m/s2 Assignment: WS1 #1-6 WS2 #1-3