A steel shuttle is pulled along a rail, what is its initial acceleration?

[potatotimer]

Homework Statement

Question: a machine has a 760g steel shuttle that is pulled along a square steel rail by an elastic cord. the shuttle is released when the cord has a 25N tension at a 45-degree angle what is initial acceleration?

Relevant Equations

F = ma or F/m = a

it sounds like you just need to use F/m = a which gives 25 / .76 = 32.89 = a
this didn't work so I tried to get the x component of acceleration so I did 32.89cos(45) = 23.26 and this didn't work.

what am I missing, the force is tension right so it should be 25N?

 

[jbriggs444]

Homework Statement:: Question: a machine has a 760g steel shuttle that is pulled along a square steel rail by an elastic cord. the shuttle is released when the cord has a 25N tension at a 45-degree angle what is initial acceleration?
Relevant Equations:: F = ma or F/m = a

it sounds like you just need to use F/m = a which gives 25 / .76 = 32.89 = a
this didn't work so I tried to get the x component of acceleration so I did 32.89cos(45) = 23.26 and this didn't work.

what am I missing, the force is tension right so it should be 25N?

Two possibilities come to mind. First, have you rounded to an appropriate number of significant figures? Second, have you been studying friction and, if so, would the friction of steel on steel come into play?

 

[potatotimer]

Two possibilities come to mind. First, have you rounded to an appropriate number of significant figures? Second, have you been studying friction and, if so, would the friction of steel on steel come into play?

yeah its friction
rereading made me realize that friction does need to be considered which for a steel on steel collision u = 0.8
so the acceleration is 25cos(45) - .8*.76*9.8
thanks for the help :)

 

[haruspex]

- .8*.76*9.8

Two errors in there.