Search
Ask a question
0

Find the tension?

Luke Autbeloe twirls a 750 gram mass on the end of a 0.82 meter string. Find the tension at the top and bottom of the orbit. Assume the mass's velocity at both top and bottom is 3.7 m/s.

2 Answers by Expert Tutors

Tutors, sign in to answer this question.
Brad M. | Professional Tutor: STEM plus Business, Accounting, and InvestmentProfessional Tutor: STEM plus Business,...
4.9 4.9 (219 lesson ratings) (219)
1
Check Marked as Best Answer
Hey Sun -- at bottom, the string feels V*V/r plus g ... at top, V*V/r minus g ...
 
V*V ~ 3.5*4.0 ~ 14 m-m/s/s ... V*V/r ~ 14/0.82 ~ 16.8/0.98 ~ 17 m/s/s ...
 
BOTTOM: 3/4 kg with 27 m/s/s ~ 21N ... TOP: 3/4 kg with 7 m/s/s ~ 5N  :)
Kirill Z. | Physics, math tutor with great knowledge and teaching skillsPhysics, math tutor with great knowledge...
4.9 4.9 (174 lesson ratings) (174)
0
The tension is largest at the bottom, equals to the sum of gravitational and centripetal forces. At the top the tension is the difference between the centripetal force and the gravitational one. Centripetal force is Fc=mv2/R. Here R is the radius, which is the length of the string.