resolving forces again, nowhere else to post this

red and white kop!

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Jun 15, 2009
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a block of mass 20kg is held in equilibrium on a plane by means of a string which is at an an angle of 25° to the greatest slope of the plane. the plane is at 40° to the horizontal.
show that the tension in the string is about 142N
i thought this would be pretty straightforward but i just don't get 142N! i mostly used 200cos60° = Tcos25° but this doesn't wrok, why? are there forces i am missing? no friction btw
 
red and white kop! said:
a block of mass 20kg is held in equilibrium on a plane by means of a string which is at an an angle of 25° to the greatest slope of the plane. the plane is at 40° to the horizontal.
show that the tension in the string is about 142N
i thought this would be pretty straightforward but i just don't get 142N! i mostly used 200cos60° = Tcos25° but this doesn't wrok, why? are there forces i am missing? no friction btw

200cos50° = Tcos25°
 
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