5 SHM Problems i can't get HELP

[gf_24]

5 SHM Problems i can't get :( HELP!

http://imageshack.us/a/img201/3924/sadv.png

Okay so these are the last 5 problems that I'm stuck on... I've tried a lot and no success, if anyone can please show me the work on how to get them... I've tried all 4 and will explain what I did

1) I found the mass easily but do not know where to go from here...

2) This is my work and it was wrong
0.8kg (m) x 9.8m/s^2 (g) = F
7.84N = F
-----------------------------
F = kx
7.84N = 20N/m × x
7.84/20 = x
0.392 = x

3) I found A-max using A-max = w^2
Plugged that into the equation Acceleration = - Aw^2 sin (wt + ∅) to find t.
Then plugged t into X = Asin(wt+∅) to find it's position... both of which were incorrect

4) I found the positions successfully.. tried to plug those values into the given equation to
find time and no luck...

5) I'm not yet 100% with pendolums so i'll do a little more studying on this one

--------------------------------------------------------------------------------------
Any help on these would be greatly appreciated thank you all :)

 

[SammyS]

[/PLAIN]http://imageshack.us/a/img201/3924/sadv.png[/PLAIN]

Okay so these are the last 5 problems that I'm stuck on... I've tried a lot and no success, if anyone can please show me the work on how to get them... I've tried all 4 and will explain what I did

1) I found the mass easily but do not know where to go from here...

2) This is my work and it was wrong
0.8kg (m) x 9.8m/s^2 (g) = F
7.84N = F
-----------------------------
F = kx
7.84N = 20N/m × x
7.84/20 = x
0.392 = x

3) I found A-max using A-max = w^2
Plugged that into the equation Acceleration = - Aw^2 sin (wt + ∅) to find t.
Then plugged t into X = Asin(wt+∅) to find it's position... both of which were incorrect

4) I found the positions successfully.. tried to plug those values into the given equation to
find time and no luck...

5) I'm not yet 100% with pendolums so i'll do a little more studying on this one

--------------------------------------------------------------------------------------
Any help on these would be greatly appreciated thank you all :)

Hello gf_24. Welcome to PF !

Please include at most, two questions/problems per post. (See the rules for this Forum.)

 

[micromass]

Let's do questions (1) and (2) in this thread. Please create another thread for the other questions.