 #1
 7
 0
Homework Statement
A muscle builder holds the end of a massless rope. At the end of the rope, a 15 kg ball is hung as shown in the figure. What is the tension in the rope if the angle [tex]\theta[/tex] in the drawing is 4.5[tex]^{}o[/tex]?
Homework Equations
g = 9.8m/s[tex]^{}2[/tex]
F = mg
Trigonometrical functions
The Attempt at a Solution
I attached a picture. My answer is just totally wrong... but I have no idea what I'm doing wrong. Please could you help out. I apologise for any stupid mistakes!
The ball is being pulled by the two hands, forming a triangle that can be divided into two right triangles with sides labeled a1, b1, c1 and a2, b2, c2 respectively.
θ Is given as 4.5°
b1 = b2 = mg = 9.8N x 15N (weight of ball given as 15kg = 15N, gravitational pull is 9.8m/s2 = 9.8N)
= 147N
The tension of the rope would equal the force created by the hands pulling (a1 and a2) and a1 = a2.
sinθ = a1/b1
∴ a1 = b1 sinθ
= (147N)sin4.5°
= 12N
Attachments

187.5 KB Views: 276