#Circular Motion

29 messages · Page 1 of 1 (latest)

honest hedge
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How do I do q6

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native salmonBOT
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spiral jasper
honest hedge
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I learn this in maths

spiral jasper
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Stop joking around

honest hedge
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?????

dull haven
# honest hedge How do I do q6

They are asking whether for the given values would the Bob complete an entire rotation or would the string slacks before completing the circle

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Use energy conservation and Newton's second law

unique valley
blissful hare
spiral jasper
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Uh ok

blissful hare
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basically we have a bob attached to a string which is moving in a vertical circle

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a) It's given that u^2=2g

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mass of bob is 0.4kg and length of string is 0.3m

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I will use energy conservation and Free body diagrams

normal creek
unique valley
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*and further

normal creek
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ohhhh i didnt know it is taught in only under physcs here

blissful hare
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i)when v>/=√5gl where l is the length of the string and v is initial velocity the bob completes the entire vertical circle
ii)when √2gl<v<√5gl the bob does note complete the circle the string becomes slack midway between completing the semi circle and full circle
iii)when v=√ 2gl it completes a semicircle and oscillates in it
iv)when v<√ 2gl it lies just below the semicircle

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if you want the derivation just look it up somewhere as it will be quite long

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or you could do it yourself by using energy conservation and FBDs

blissful hare
# honest hedge How do I do q6

using this you can check the kind of motion the bob shall perform keep in mind that it is independent of the mass of the bob and only depends upon its initial velocity and length of the pendulum value of g being a constant of course

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a) u^2=2g
√5gl=√5g*0.3=√1.5g seeing the i) relation I can say that it completes full circle

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b) u^2=g u=√ g
u=√5gl=√1.5g
u=√2gl=√0.6g
seeing relation ii) I can say that it completes only a part of circle (between full and semi) and then continues in a parabolic path afterwards

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c) u^2=0.5g
u=√0.5g
seeing relation iv) It will just oscillate lower than a semi circle only like a pendulum

honest hedge