Question

A string of mass m=.1kg is stretched to where its length is L=20m. What is the tension force applied to the string if it takes a pulse 2 seconds to get from one end to the other?

m=kg
L=20m
T=4s
mass density =m/L = .1/20 = kg/m
Tension =?

I know v=sqrt(F_t/mass density) But I'm given two unknowns. How would I find velocity?

Answer 1

Well, you said v = sqrt(F/.005)
you also said the pulse goes 20 m in 2 s
so
v = 20/2 = 10 m/s
so
10 = sqrt (F/.005)
100 = F/.005
F = .5 N