Core Concepts: Finding and Manipulating Equations Centripetal Force Angular Velocity Energy Work Opener: Equation Review Kahoot! Time 10 minutes Go to www.kahoot.it and enter the code on the screen to join the quiz! We will be reviewing equations from every chapter that s been covered so far. Activity #1: Skip the Math Time 2 minutes In this activity, we will look at uniform circular motion problems. These problems will have no numbers associated with them. Work in small groups at tables and find the following information: Equations needed Which equations correlate to different parts of the problem Rearranged equations What the final value would represent Units on final value
1) Joe is driving a car down the freeway and he goes around a banked curve. The car has a mass, and a velocity. If the radius of the curve, angle of the bank, and coefficient of static friction are given, how would you determine if Joe s car skids or not as he drives around the corner? What supplies the centripetal force in this scenario? 2) Chris is swinging a bucket of water in a vertical circle over his head. If you were given the bucket s mass, the length of the rope, and the velocity, how would you determine the centripetal force? Draw 2 free body diagrams to describe the motion: one where the bucket is at the bottom of the circle, and one where the bucket is at the top, directly over his head. From this information, come up with an explanation as to why the water doesn t fall on his head.
Activity #2: Chalk Relay Time 2 minutes These problems will be solved at the boards in small groups. The chalk must change hands from one line to the next in the calculation. Each group will attempt one question, and then share their answers with the class. Equations you may need: 1 inch = 2.4 cm s = r ω = θ t a c = v2 = r ω2 r F c = ma c ω = 2πf 1) Cam is being careless and accidentally drops a piece of gum onto the rim of an LP vinyl record, as it spins on a turntable. The gum has a mass of 2.1 grams. LP s are 12 inches in diameter, and they spin at 33.33 revolutions per minute. a) How long does it take the gum to complete one full rotation? b) What is the centripetal force exerted on the gum? 2) A car driving around a banked curve. It has a mass of 990 kg, and a velocity of 11.2 m/s. There is friction between the wheels and the tires, or s = 0.30. If the angle of the bank is 12 o, what is the centripetal force that keeps the car in circular motion? 3) A remote-controlled helicopter being flown in a circle. It takes 12 seconds to complete this a circle, which is in the horizontal plane. What is its angular acceleration? What is its tangential acceleration? What is its period?
Activity #3: Think, Pair, Share You will get minutes to work on the problem, 3 minutes to collaborate with your table, and then volunteers will share their findings with the room. Time 20 minutes Equations you may need: E k = 1/2mv 2 E g = mgh E g = - Gm 1 m 2 / r W = Fdcos E 1 = E 2 1) Megan is running. Her mass is 66.4 kg, and her velocity is 4.0 m/s. What is her kinetic energy? If she were travelling at the same speed but falling off an 8.0 metre ledge, what is her gravitational energy? 2) Sarah is trying to move a box with a mass of 71 kg by pushing it across the floor. There is kinetic friction between the box and the floor, of coefficient 0.62. If she pushes with a force of 106.0N and the box moves a total of 20.00 metres, how much work is done on the box?
Closer Time: minutes To end for the night, we will share ideas for study skills on how to be successful in this course. Go to www.menti.com and send in what study skills, habits, and helpful hints help you learn, and we ll create a word cloud in the workshop! (You can answer more than once!). Resources for You: Physics Drop In Centre - HP 3349 Monday 11:30am 1:30pm Wednesday/Friday 1:00 pm 2:30 pm Tuesday/Thursday 11:30 am 1:00 pm Science Student Success Centre - HP 3431 https://sssc.carleton.ca/ Dr. Donkers Office Hour - 3313HP Tuesday 10:30 to 11:30 and Thursday from 13:00 to 14:00 or by appointment. Dr. Vincter s Office Hour - 248HP Tuesdays 11am-noon and 1pm-2pm or by appointment.