A girl with a mass of 22 kg is playing on a swing. There are three main forces acting on her at any time: gravity, force due to centripetal acceleration, and the tension in the swing's chain (ignore the effects of air resistance). At the instant shown in the image below, she is at the bottom of the swing and is traveling at a constant speed of 2 m/s. What is the tension in the swing's chain at this time? (Recall that g = 9.8 m/s2)

A. 180.9 N
B. 117.4 N
C. 97.5 N
D. 237.6 N

Question

A girl with a mass of 22 kg is playing on a swing. There are three main forces acting on her at any time: gravity, force due to centripetal acceleration, and the tension in the swing's chain (ignore the effects of air resistance). At the instant shown in the image below, she is at the bottom of the swing and is traveling at a constant speed of 2 m/s. What is the tension in the swing's chain at this time? (Recall that g = 9.8 m/s2)



 		A.	180.9 N
 		B.	117.4 N
 		C.	97.5 N
 		D.	237.6 N

vincent-lyon.fr · Answer

The question is wrong: at any instant, there are only 2 physical forces acting on the girl.

anonymous · Answer

The wording is bad, since the centripetal acceleration is CAUSED BY the net Force (T-mg).
But the question can be answered ... just plug'n chug:  T - mg = m v^2/r