# Circular Motion Circular Motion Suppose an object is moving at a constant speed in a circular path. In which direction is the velocity? The speed of the object moving in a circular path is constant, but we say

that it is accelerating. Why? What needs to be present to cause the acceleration? In which direction is it? Centripetal Force

The inward force that keeps an object moving in a circle What would happen if the centripetal force were removed? The formula for centripetal acceleration

(acceleration caused by a centripetal force) is: Units are meters per second squared (m/s2) The equation for centripetal force comes from Newtons Second law Units are newtons (N)

Centrifugal force: the apparent outward force felt by an object that is moving in a circle This is not really a force but rather a feeling of resistance due to the inertia of the object as it is pulled toward the center of centripetal force. Equation for Average speed

R: Radius (meters) Pi: 3.14 T: Time (seconds)

V: velocity (measured in m/s) Equation for Average speed

Frequency= Rotations per minute Newtons Law of Universal Gravitation Gravity is a force of attraction

between two objects because of their mass. Anything with mass exerts a force of gravity on any other thing with mass and viceversa Discussion: what is the relationship between mass and the force gravity that mass exerts? If the mass of an object is

tripled, how and by what factor does the force of gravity change? Discussion: What is the relationship between adding distance and the force of gravity between two objects? If the separation distance is tripled,

Newtons Law of Universal Gravitation Newtons Law of Universal Gravitation states the force of gravity exerted by an object or between two objects is Directly

proportional to the masses and directly inversely proportional to the separation distance Newtons Law of Universal Gravitation