Centripetal Force Mini Lab and Lecture EN_____ In this activity we will investigate objects moving in a circular or semi circular motion in order to better understand the formation of stars and our solar system. First, take a ball and string and try swinging the ball in a uniform circle and speed. Since keeping an object at a constant speed is challenging to say the least, let’s take the average speed. 1. Swing the ball 10 times in a circle without changing the length of the string from your grip to the ball. 2. Record the time it takes to complete 10 cycles. ____________ 3. Record the distance of the string. ____________ The PERIOD of motion is the time it takes to complete one rotation. T= rotations/time How far does the ball travel in one rotation? How can we calculate the distance traveled by a circular path? Speed of an object moving in a uniform circular path is Show your work for your trial: Circumference: Period (T) = Velocity: OK, so we’ve figured out the speed of the mass, but is it accelerating? Remember that the mass is traveling at “constant” speed, However acceleration is defined as: So how does the velocity of the mass change with respect to time? Imagine throwing a discus. Explain the behavior of the discus after you spins around a couple of times and release it. Think about swinging the ball in a circle. What did your arm feel like? The acceleration of an object in circular motion is always towards the …. This is the definition of centripetal which means center seeking. Notice that the direction of the velocity at any time is .... So even though it may be traveling at a _______________ ___________________ anything traveling in a circular path is _________________________ because the _________________ of its velocity is always changing Whenever an object is accelerated there must be a This force is known as the ___________________ _____________ Fc. This is not a new force, it is simply the net force that accelerates an object towards the center of its circular path. Examples: 1. A mass is twirled in a circle, the centripetal force is provided by ___________ 2. When a car rounds a corner on a highway, the centripetal force is provided by ____________ 3. When the Moon orbits the Earth, the centripetal force is provided by _______________ Challenge question: A Plane makes a complete circle with a radius of 3622m in 2.10 min. What is the speed of the plane? One last note on a little thing call centrifugal force. While centripetal means center ______________, centrifugal means center - ________________ . An inertial frame of reference is one where Newton’s Laws are ________. In an inertial frame of reference, centrifugal force is actually the apparent force – IT DOES NOT EXIST. It is simply the apparent force that causes a revolving or rotating object to move in a straight line. Example: When riding in the backseat of a car that is turning a corner, you slide across the seat and lean to the side of the car opposite the center of the turn. Explain where the force is going towards.