Forced Oscillations: Period & Amplitude Calculation

[nemzy]

A 2.00 kg mass attached to a spring is driven by an external force F = (2.00 N) cos (3t). Assume that the force constant of the spring is 25.0 N/m.

(a) Determine the period of the motion

(b) Determine the amplitude of the motion


FOr part A, i tried the T=2(pi)/w formula, and i got the wrong answer...what am i doing wrong?

For part B, the book says to use this formula:

A= Fo/m / square root of [ (w^2-wo^2)+(bw/m)^2 ]

the Bw/m^2 is irrelevant since B=0...

But what is Fo? Is this how u are suppose to solve for the amplitute for this problem? thanks

 

[remcook]

first write down the equation of motion before plugging in some formulas. all these oscillation questions you have, have the same kind of equations of motion. first write them down and then solve these equations. don't rely on rules of thumb.

 

[HallsofIvy]

What course is this? These look like problems from a differential equations course, but you haven't said anything about solving any differential equations.

PLEASE tell us what your notation means in this particular problem. There is no way we can say what B or Fo mean. Those have to be defined when the formulas are given.

 

[nemzy]

B=constant related to the strength of the resistance force

and Fo is

F(t)=Fo(sin(wt))