Question

The position of a 50 g oscillating mass is given by x(t)=(2.0cm)cos(10t−π/4), where t is in s. If necessary, round your answers to three significant figures. Determine:
the amplitude
2cm
the period
.628s
the spring constant
5N/m
the phase constant
-.785rad
the initial coordinate of the mass
1.41cm
the initial velocity
14.1 cm/s
maximum speed 20 cm/s
what's the total energy?

Answer 1

ode or physics?

Answer 2

physics

Answer 3

ah energy, physics

Answer 4

ok, what eq ya gonna use?

Answer 5

thats what idk

Answer 6

oh it just wants total, so you have to think about all the energy at this point

Answer 7

ie is it moving, what type of energy is that? is it stopped?

Answer 8

then remember conservation if you have anything you have to solve for

Answer 9

is there a formula?

Answer 10

formula for conservation yes, for total energy, other than the obvious, not that I know of

Answer 11

^that is why I hate physics :)

Answer 12

I assume you know how to find spring energy, yes?

Answer 13

\[F=\frac{ 1 }{ 2 }kx^2\]

Answer 14

you are both welcome to take this off of my hands, I am probably not as good at explaining this as either of you could be

Answer 15

im not that great either

Answer 16

The energy of the oscillating mass is made up of potential energy (stored in the energy of the spring) and kinetic energy. When KE is max, PE is zero. When PE is max, KE is zero. You already found max velocity to an earlier question. 1/2 * m * v^2 is the max. KE and at that instant PE will be zero. So that is the total energy.

Answer 17

so the answer is 0

Answer 18

\[
\text{Total Energy } = KE_{\text{max}} = \frac 12mv_{\text{max}}^2 =
\frac 12 * \frac{50}{1000} * \left( \frac{20}{100} \right)^2
\]

Answer 19

You are using ME=ME=ME here,

Answer 20

(that is the deeper concept)

Answer 21

what does ME stand for?

Answer 22

\[
\text{Total Energy } = KE + PE = KE_{\text{max}} + 0 = 0 + PE_{\text{max}}
\]Here we use:
\[
\text{Total Energy } = KE_{\text{max}}
\]

Answer 23

Mechanical energy, but that is just the notation that represents conservation of energy from x=0, x=1/2max, x=max

Answer 24

ok so i solved the top one and got .001

Answer 25

0.001 Joules or 0.001 N-m.

Answer 26

ME means mechanical energy

Answer 27

Joules ?

Answer 28

unit of energy. 1 Joule = 1 Newton-meter.

Answer 29

so 0.001 N-m

Answer 30

Yes.

Answer 31

is that the answer?

Answer 32

Yes.

Answer 33

thanks

Answer 34

yw.

Answer 35

nice work