Up force from wire at tip of rod = T sin 30
Down force at rod center = 120 N
moments about rod at wall
T sin 30 (L) = 120 (L/2) = 60 L
T = 60 /sin 30 = 60/0.5 = 120
There is a right angle triangle:
-.-
-...-
-......-
-.........- T (wire)
-............-
-...............-
------------------ 30 degrees
....--.....--.....rod
....--.....--.....
....--.....--.....
....---------.....
....-.......-.....
....-.......-.....
....-.......-.....
....---------.....
sign 120n downwards
The weight of the sign and rod act through the centre point of the ro. The value w is 120n. The anle between wire and rod is 30 degrees.
Calculate the tension in the wire
The mark scheme says T=60/sin 30 or 60cos60
T=120N
But i dont understand where the numbers came from and how it was worked out please write down how you do it step by step!
2 answers
the sign in the center of the rod? Let L be the length of the rod.
so it is critical to understand the rod connection to the wall. Is there any vertical force exerted on the wall, and is the wall exerting any moment on the rod.
without that knowledge, the mark scheme is useless.
so it is critical to understand the rod connection to the wall. Is there any vertical force exerted on the wall, and is the wall exerting any moment on the rod.
without that knowledge, the mark scheme is useless.
2 answers