Circular Motion
The period of the ball is the time to orbit once. The frequency is the number of orbits in one second. The speed is the distance traveled in one period
Radius
Centripetal Acceleration Acceleration means a change in speed or in direction. Has the ball accelerated in the collision?
Has the ball accelerated as it orbits?
Direction of Acceleration. Centripetal acceleration is always towards the centre of the circle
What two things affect the size of the centripetal acceleration What two things affect the size of the centripetal acceleration? (remember a change in direction means acceleration)
Both balls have the same radius (1) Speed Both balls have the same radius Which ball accelerates most? SLOW FAST
Both balls have the same speed (2) Radius Both balls have the same speed Which ball accelerates most? BIG RADIUS SMALL RADIUS
Centripetal Acceleration As speed increases, centripetal acceleration As radius increases, centripetal acceleration increases decreases
The equation for centripetal acceleration is……………
Centripetal Force When something moves in a circle, it accelerates towards the centre. This requires a Its called centripetal force and is always towards the FORCE CENTRE
When acceleration is zero, you feel no sideways force v Speeding up When you accelerate forward you imagine a force backward a v Slowing down When you accelerate backward you imagine a force forward a v
Going Around the Bend you are taking a DVD back to the shop. Its on the dashboard. What happens when you turn a corner?
velocity centripetal force
Imaginary force a Centripetal force
Centripetal Force is any force that keeps things moving in a circle Centripetal Force is any force that keeps things moving in a circle. What provides the centripetal force for…… A ball on a string Tension A mouse on a spinning turntable Friction
Centripetal Force Equation
What happens if the centripetal force is removed? What direction will the car slide when it hits the ice? ICE
Which law does this illustrate? Newton’s 1st Law. An object will have constant velocity unless a net force acts on it.
Centripetal force
Which side of the road should you spectate from?
Excellence Examples 1.0 kg The maximum breaking strain of the string is 25 N. The radius is 1.0m. Calculate the minimum period before the string snaps. Explain how the ball can be moving at constant speed even though there is an unbalanced force on it