## spring problem

xopip
Posts: 2
Joined: Wed May 23, 2018 3:28 am

### spring problem

Hi I need a question answered. I dont know if anyone is here but the problem is

A 0.5 kg mass oscillates at the end of a spring with an amplited of 0.4 meters. The mass completes 2.8 oscillations each second.
a. What is the period of teh oscillations?
b. What is the maximum speed of the mass as it soscillates?

part a is .357143 (found formula for that one). i need help with part b, is it 1/2mv^2+1/2kx^2?

jeff
Posts: 38
Joined: Mon Mar 05, 2018 11:54 pm

### Re: spring problem

Hi xopip,
Hi I need a question answered. I dont know if anyone is here but the problem is

A 0.5 kg mass oscillates at the end of a spring with an amplited of 0.4 meters. The mass completes 2.8 oscillations each second.
a. What is the period of teh oscillations?
b. What is the maximum speed of the mass as it soscillates?

part a is .357143 (found formula for that one). i need help with part b, is it 1/2mv^2+1/2kx^2?
That's not the best approach to use for this one, because we don't know the spring constant k.

Instead, the thing to remember is that there are formulas relating the maximum values: maximum acceleration, maximum speed, and maximum distance (amplitude). The problem gives us the amplitude A, so we can relate that to the max speed using:

v_max = w A
(here v_max is maximum speed, w is angular frequency, and A is amplitude)

or

v_max = (2 pi f) A
(here f is frequency)

They give us f=2.8 Hz and A = 0.4 m, so we can find v_max right away.

Does that make sense? Be sure to ask if you still have questions.

xopip
Posts: 2
Joined: Wed May 23, 2018 3:28 am

ok now i got it
thx