Recently started out on springs, few problems, help greatly appreciated
1) Particle of mass 3kg is attached to one end of a light elastic string, natural length is 1m, modulus of elasticity is 14.7N. The other end of the string is attached to a fixed point. Particle is held in equilibrium by a horizontal force of 9.8N, string inclined to verticle at an angle x.
a) value of x
b) extension of string
c) If the horizontal force is removed, find the magnitude of the least force that will keep the string inclined at the same angle?
I have worked through a and b, however I am not sure how to approach part c. Here are my workings of a and b... ( I have also attached a diagram)
a) 9.8 = sin x T and T cos x = 3g, therefore tan x = 1/3
b) choosing 9.8 = sin x T, T = 9.8/sin x.
Setting T = 14.7s/1 gives s = 2.11 ( where s is the extension in the string)
Turn on thread page Beta
M3 springs/strings watch
- Thread Starter
- 01-04-2011 18:12
- Study Helper
- 01-04-2011 18:25
Triangle of forces.
You know one force (3g)
You know the direction of the tension.
Draw a diagram - you need this!
What's the third force that creates equilibrium, and when will it be a minimum.