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THANK YOU…. To all who attended ‘It Gets Better,’ & To all who are participating in the Day of Silence. Your actions are making a positive difference for so many members of the Robbinsville community. . What is the weight of the unknown box? . 4.5 N 60 N 160 N 240 N 540 N 1800 N
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THANK YOU….To all who attended ‘It Gets Better,’&To all who are participating in the Day of Silence Your actions are making a positive difference for so many members of the Robbinsville community.
What is the weight of the unknown box? • 4.5 N • 60 N • 160 N • 240 N • 540 N • 1800 N • 4800 N • 10,800 N • None of the above • Not sure/not enough info
Take out the HW from last night • We are going over #21, 33, 38
21a. Torque = Force x Lever Arm Torque = 50N * 0.2 m Torque = 10 N m Part b) STOP – before doing any math, should we expect a larger or smaller torque? (same force but now a larger lever arm) Larger! Torque = Force x Lever Arm Torque = 50N * 0.5 m Torque = 25 N m
Mass of the rock? STOP – which must have the larger mass??? The rock!!! Smaller lever arm! F * LA = Torque = F * LA mass * 25 cm = 1kg * 50 cm mass * 25 cm = 50 cm kg Mass = 2 kg Challenge – what is the WEIGHT of the rock? Weight = mg Weight = 2 kg * 9.8 m/s2 Weight is approximately 20 N
38) 200 g * 30 cm = 500 g * LA 6000 cm g = 500 g * LA LA = 12 cm…. BUT WE ARE NOT DONE! The question asks at what mark should it be placed? If it’s suspended from 50 cm… Then 50 cm + 12 cm = The 62 cm mark!
POST LAB • Go to test seats • Open notes; NOT open text • EXTRA CREDIT – YOU MUST SHOW WORK next to each Mystery Box answer line in order to earn points • NO TALKING UNTIL TEACHER SAYS ITS OK – if you talk before you are given permission, you WILL LOSE POINTS. • When you are done, turn in post lab and take a copy of 11.5-11.7 notes • SILENTLY return to test seat and work on notes.
In which image (a or b) do you think the gymnast SPIN FASTER? • A • B • Same in both • Not sure/not enough info
In which image (a or b) do you think the gymnast has the greatest ROTATIONAL INERTIA? • A • B • Same in both • Not sure/not enough info
In which image does the man have the greater rotational inertia? A B • A • B • Same in both • Not sure/not enough info
In which image does the man have the greater rotational velocity? A B • A • B • Same in both • Not sure/not enough info
In which image does the man have the greater angular momentum? A B • A • B • Same in both • Not sure/not enough info
NEXT CLASS • You will work on a short, hands on lab • You will have the remainder of class to work on your study guide • The study guide is due at the end of next class for +5 • Your HW next class will be to prep for the Ch 10 & 11 test