review 2014.notebook January 25, 2017 r s = +151 km 1.51 x 10 5 m r e = 6.38 x 10 6 m r os = 6.53 x 10 6 m

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1 A satellite is 151 km from the earth's surface and has a period of 1.41 hours. a) What is its frequency b) What is its velocity? c) What is its centripetal acceleration? d) What centripetal force is applied if it is 1550 kg? r e = 6.38 x 10 6 m A satellite is 151 km from the earth's surface and has a period of 1.41 hours. a) What is its frequency b) What is its velocity? c) What is its centripetal acceleration? d) What centripetal force is applied if it is 1550 kg? r s = +151 km 1.51 x 10 5 m r e = 6.38 x 10 6 m r os = 6.53 x 10 6 m r e r os 151 km T = 1.41 hr 5080 s f = 1/T = 1.97 x 10 4 rev/s ros orbital radius of satelite (distance from center of earth) a) v = 2πr/T = [2π(6.53 x 10 6 m)]/5080 s = 8080 m/s b) a = 4 π 2 r/t 2 = [4π 2 (6.53 x 10 6 m)]/(5080 s) 2 = 10.0 m/s 2 c) Fc = m4 π 2 r/t 2 = 1550 kg[4π 2 (6.53 x 10 6 m)]/(5080 s) 2 = 15,500 N A kg ball is kicked at a 34.0 o angle at 33.0 m/s. a) How long is it in the air? b) How far does it go?... c) How high does it go? A kg ball is kicked at a 34.0 o angle at 33.0 m/s. a) How long is it in the air? b) How far does it go?... c) How high does it go? 1

2 review 2014.notebook Bad Billy runs around a 50.0 m radius circular track in 1.33 minutes. a) What is his velocity? b) What is his centripetal acceleration? c) What is μ if he is 88.0 kg? (he's running as fast as he can without slipping) Bad Billy runs around a 50.0 m radius circular track in 1.33 minutes. a) What is his velocity? b) What is his centripetal acceleration? c) What is μ if he is 88.0 kg? (he's running as fast as he can without slipping) r = 50.0 m T = 1.33 min 79.8 s v =? ac =? μ =? a) v = 2πr/T = [2π(50.0 m)]/79.8 s = 3.93 m/s b) a = 4 π2r/t2 = [4π2(50.0 m)]/(79.8 s)2 = m/s2 c) μ = Ff/FN = Fc/Fw = mac/mg = ac/g = m/s2/9.81 m/s2 =.0316 A poplar ride at theme parks is the "puke meister". It has a movable floor that lowers when the ride reaches maximum speed and the riders are held in place at the walls of the rides of the wall by friction. What is μ if "r" is 5.0 m and the period is 2.0 s? A poplar ride at theme parks is the "puke meister". It has a movable floor that lowers when the ride reaches maximum speed and the riders are held in place at the walls of the rides of the wall by friction. friction is "up" because gravity wants to pull junior down Ff Ff center of rotation. FN = Fc Fc = F N Fw mv2/r = Ff/μ FN = F c mv2/r = mg/μ v2/r = g/μ μ = gr/v 2. Fc = FN Ff = μfn FN = Ff/μ Ff = Fw center of rotation mv2/r = Ff/μ Fw mv2/r = mg/μ v2/r = g/μ m's cancel Ff = μfn FN = Ff/μ Ff = Fw v = 2πr/T v = 2π(5.0 m)/2.0 s v = 16 m/s μ = [9.8 m/s2(5.0 m)]/(16 m/s)2 μ = 0.19 μ = gr/v2 solve for μ 2

3 NASA developed plans for a space station that would be a lot like a bike tire. It would have to be about 1.2 km in diameter and maintain 1g of centripetal acceleration at the inside of the outer rim. What velocity would it have to maintain and what would its period be? NASA developed plans for a space station that would be a lot like a bike tire. It would have to be about 1.2 km in diameter and maintain 1g of centripetal acceleration at the inside of the outer rim. What velocity would it have to maintain and what would its period be? A 35.0 g bullet is fired horizontally at 444 m/s from a horizontal height of 1.20 m. How far does it go? dia = 1200 m r = 600 m a = 1g = 9.8 m/s 2 v =? T =? a = v 2 /r v = ar = 9.8 m/s 2 (600 m) = 77 m/s v = 2πr/T T = 2πr/v = 6.28(600 m)/77 m/s = 48.9 s 3

4 A 35.0 g bullet is fired horizontally at 444 m/s from a horizontal height of 1.20 m. How far does it go? m = 35.0 g.0350 kg v = 444 m/s d y = 1.20 m d x =? d = 1/2at 2 t = 2d/a = 2( 1.20m/ m/s 2 ) =.495 s What period would you have to swing your sling shot at to hit a target 8.0 m away? r = 1.0 m Your d y is 1.7 m d x = v x t = 444 m/s (.495 s) = 220 m x What period would you have to swing your sling shot at to hit a target 8.0 m away? r = 1.0 m Your d y is 1.7 m A Ferris Wheel is 39.0 m across (diameter). Its period is 45 seconds. You are 65 kg. What is your velocity, your acceleration, the centripetal force to keep you in circular motion? x 4

5 Ferris Wheel is 39.0 m across. Its period is 45 seconds. You ar 65 kg. What is your velocity, you acceleration, the centripetal force to keep you in circular motion? A 555 g ball is kicked with an initial velocity of 17.0 m/s at an angle of How long is it in the air? how high does it go? how far does it go? A 1205 kg car circles on a 75.0 m (radius) track at 94.3 mph. what is it a c? what is F f? What is its period? What is µ if you're cornering as fast as you can? m = 1205 kg r = 75.0 m v = 94.3 mph a c =? F f =? 11,820 N 42.2 m/s a = v 2 /r a = (42.2 m/s) 2 /75.0 m = 23.7 m/s 2 F f = ma c = 1205 kg(23.7 m/s 2 ) = 28,600 N v = 2πr/T T = 2πr/v = 6.28(75 m)/42.2m/s = 11.2 s What is the acceleration of a 1.22 kg box sliding down a ramp that is 66.0 cm off the ground at an angle of if µ is.222? µ = F f/f N = 28,600 N/11,820 N =

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