PhysicsMrs. Coyle

Static Equilibrium: “The Hanging Sign Problem”

-How do you calculate the tensions in the strings?-How do the angles affect the tensions?

EquilibriumFnet = 0a=0

Static Equilibrium: the object is at rest.Dynamic Equilibrium: the object is moving at

constant velocity.

The Equilibrant is a force that is exerted on the system to bring it to equilibrium.

Example 1

a)Calculate the tension in each string. The mass of the sign is 2kg and the angles formed between each string and the sign are 300.

b)If the angles were 10o, what is the tension and how does it compare with the answer to a)?

Answer: a) T1 = T2 = 20N

b) T1 = T2 = 58N

In which case is the tension greater?

http://wwwrcamnl.wr.usgs.gov/sws/SWTraining/cableways/design.htm

Do the angles affect the tension?Examples:

Telephone or electrical wires.Picture frame wire.

Example:            

A sign is suspended as shown above.a) Calculate the tension in each string.

b) Which tension is greater T1 or T2 and how does that correlate with the angles?

Answer: T1 = 538N, T2 = 439N

Example 2 T1 T2

Example 3

A sign is suspended as shown above.   a) Calculate the tension in each

string.  b) Which tension is greater T1 or T2

and how does that correlate with the size of the angles?

Answer: T1 =289N, T2 =144N

T1 T2