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What distance does the block slide?

  • Thread starter JiJiasd
  • Start date
  • #1
7
0

Homework Statement


upload_2016-5-24_16-24-33.png


Homework Equations


m*v^2 / 2 and k*x^2 / 2 and 0,5*m*v^2

The Attempt at a Solution


[/B]
in task a I got correct answer there v = 20 m/s
in task b I got wrong answer I got the distance = 0,76 m but I should be 32 m

here is my answer :
0,5*m*(sin(30)*v) - mu * m*g*cos(30) = m*g*h
h=0,38 m
sin (30) = h/L there L is the distance of the block when it goes up
L= h/sin(30) = 0,76

What I do wrong in task b ?

Thanks

 
Last edited by a moderator:

Answers and Replies

  • #2
115
8
  • #3
36
3
I seem to get the answer on the second one to be 35.4012435624
 
  • #4
115
8
mu * m*g*cos(30)
Shouldnt this be mu*(m*g*cos(30))*h/cos(30)=mu*m*g*h?
I think so...
 
  • #5
7
0
I seem to get the answer on the second one to be 35.4012435624
What equation you did use ? thanks
 
  • #6
7
0
sin(30)v should be squared
I tried with 0,5*m*(sin(30)*v)^2 - mu * m*g*cos(30) = m*g*h
but it does not give me the correct answer
thanks
 
  • #7
7
0
Shouldnt this be mu*(m*g*cos(30))*h/cos(30)=mu*m*g*h?
I think so...
Now I tried 0,5*m*(sin(30)*v)^2 - mu * m*g*cos(30) *h/sin(30) = m*g*h
but not working
 
  • #8
36
3
I used a kinematics equation
 

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