Circular Motion Lab.doc.docx



Name ________________________Date ____________ Period ______Flying Pigs There are many things to consider when analyzing the motion of an object moving in a circular path. The forces involved, the centripetal acceleration, the tangential velocity, the radius, and so on. By the end of this activity you will be able to determine all of these things for any circular motion, but today you will be using a Flying Pig!The first thing you need to determine is the period (T) of the flying pig. The period is the time it takes for the object traveling in a cyclical motion to complete one full revolution. Here’s how you’ll do this:To complete a revolution the pig must travel through a complete circle back to where it started.Question: Do you think we should measure just one revolution?Why?You’re going to measure 10 revolutions. Watch the pig as it flies and time how long it takes to complete 10 revolutions. Record this as Time in Data Table 1.Data Table 1TrialTime (s)Period (s)Avg.123Do it again! Twice! Accuracy is king!The period is the time it takes to complete ONE revolution, so calculate Period by dividing Time by 10 for each trial.Calculate the average Period and record in Data Table 1.The next step is to find the radius of the circular motion that it taking place. That means you have to physically measure the radius of the circle the pig is making (in meters).Come up with a plan with your group members on how you are going to do this.Our plan is to:Do it! What is the radius of the motion? _____ metersDraw a diagram to the right that represents the motion taking place and label the radius.Now what? You have measured the radius and found the Period of the flying pig’s motion. What can we do from here? – This is a rhetorical question. Do not answer it.The first thing we can do is figure out the tangential velocity. Tangential velocity just means how fast the object is traveling in its circular path, or how fast it would travel in a straight line if the string were cut.The velocity equation is v = d/t. But there’s a problem. The distance the pig is traveling is along a circular path and this equation uses straight line motion. Since we are using the time for one complete circle, we can use the circumference of the circle as the distance, which is 2πr. So:RadiusPeriodv = 2πr TWhat is the tangential velocity of our flying pig? _____ m/sIf the radius of a circular motion was doubled and the tangential velocity remained constant, what would happen to the period?What would the tangential velocity be if the radius was 6.371x109 meters and the period was 3.15x107 seconds (365 days)? (This is the tangential velocity of the Earth as it spins) Since the pig is not allowed to travel in the straight line that it would normally move in, there is a force that is causing it to change its motion. Remember that a force causes acceleration. In this case we call it centripetal acceleration, and we calculate it this way:Tangential velocityRadiusac = v2 rCalculate the centripetal acceleration of the pig. ________ m/s/sWhat would happen to the centripetal acceleration if the radius was doubled?What would happen to the centripetal acceleration if the velocity was doubled?What has more of an impact on the centripetal acceleration, the velocity or the radius, and WHY?What does Newton’s first law state?So the pig should travel in a straight line, but it doesn’t, so there must be a __________ present that is changing the pig’s motion.What direction is it acting?How do you know?The force acting on the pig can be found by using Newton’s 2nd law (F = ma), but the force we would be finding is the centripetal force, and you would calculate it using the centripetal acceleration:Centripetal accelerationCentripetal forceFc = macCalculate the centripetal force of our flying pig. What happen to the centripetal force if the acceleration doubled?What would happen to the centripetal force if the mass doubled? Describe the relationship between force and mass and between force and acceleration.Conclusion Questions:Why does the flying pig not fly away in a straight line?If you were riding on the back of the pig as it flew in the circular path, what direction would you feel “pulled?” Why?What would happen to the flying apparatus if the string was cut or suddenly broken?What happens to the tangential velocity if the mass of the toy is increased?What happens to the period if the tangential velocity increased?Calculate the centripetal acceleration of an object with a radius of 3.2 m and a velocity of 8.9 m/s. ................
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