brae72

24.10.2019 • 

Physics

This probably isn't quite the question that one would expect on but i really want to know what exactly it was that i did wrong:

i was asked this question on e2020 (the e standing for education), and i was positive that i did all of the equations that i had to do right. i got the direction of r right on my first try (both ys add to zero, so the angle is automatically 0°), but i'm stumped on how i'm supposed to get 0.5n for the magnitude. if anybody knows the process that i missed, then let me know. i took a screencap of the question that this happened on for you to have a reference.

Ответ:

Rosemckinney2351

04.11.2021

Physics

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a) 4.2 m/s

b) 680 N

Explanation:

Given that

Mass of the child, m = 43 kg

Length of the chain, r = 2.94 m

Tension in the chain, T = 340 N

Then...

a) F(net) = mv²/r + mg

340 * 2 = (43 * v²)/2.94 + 43 * 9.8

680 = 43v² / 2.94 + 421.4

43v² / 2.94 = 680 - 421.4

43v² / 2.94 = 258.6

43v² = 258.6 * 2.94

43v² = 760.284

v² = 760.284 / 43

v² = 17.68

v = √17.68

v = 4.2 m/s

(b) 680 N

Conclusively, the child's speed at lowest point is 4.2 m/s

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