(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

An energetic father places his 20 kg child on a 5.0 kg cart to which a 2.0 m long rope is attached. He then holds the end of the rope and spins the cart and child around in a circle, keeping the rope parallel to the ground. If the tension in the rope is 100 N, how much time does it take for the cart to make one rotation?

2. Relevant equations

F=ma=m(w^2)r where w is omega then w^2= (2pi/T)^2)= 4 * pi^2/ T^2

since w for one rotation in the circle is equal to 2pi radians/T then F=m * ((2pi/T)^2) * r /r. The r's in the equation cancel and you are left with F= 25 * 4 * pi^2/T^2

So 100T^2=987 T=3.1 seconds but the answer is 4.4 seconds. what am I doing wrong????

3. The attempt at a solution

since w for one rotation in the circle is equal to 2pi radians/T then F=m * ((2pi/T)^2) * r /r. The r's in the equation cancel and you are left with F= 25 * 4 * pi^2/T^2

So 100T^2=987 T=3.1 seconds but the answer is 4.4 seconds. what am I doing wrong????

Thank you kindly for your help.

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# Homework Help: Analyzing motion of a cart

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