## force mass and acceleration

1. The problem statement, all variables and given/known data

A 2.00X101 kg mass is pulled upwards with constant acceleration by a cable attached to a motor. The cable can withstand a maximum tension of 5.00X102 N. What is the maximum acceleration possible?

2. Relevant equations

F=ma

3. The attempt at a solution

F=ma
F/m = a
500/20 = a
25 m/s2= a

some1 please tell me what i did wrong :-(

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 Don't forget gravity!
 You have to accout for the acceleration due to gravity! Edit: Your too fast for me Apphysicist !

## force mass and acceleration

Indeed! F=ma is your net force = m* net acceleration. If you apply your maximum tension upward, gravity still acts downward (sum the forces for your net force, don't forget that gravity gets a minus-sign because it acts in the opposite direction of your upward tension). Then use F=ma.

 so the formula would be changed to F= (mg)a ?

 Quote by kamalpreet122 so the formula would be changed to F= (mg)a ?
No, it would be changed to (T-mg)=ma.

Do you see why?

 yeaaa kinda ..soo the total weight subtracted from Tension gives me the net force then i apply the forumlaa .. OH that makes so much senseee =) THNXXX :D
 man yur great =P i have a really tough question i was not able to figure out wanna help me with that :\$

 Quote by kamalpreet122 yeaaa kinda ..soo the total weight subtracted from Tension gives me the net force then i apply the forumlaa .. OH that makes so much senseee =) THNXXX :D
Right. It's much easier to think about F=ma really being:

$$\sum_{\text{all}}\bold{F}\,=\,m \bold{a}$$

So it's a sum of all your vector forces (the bold meaning it's a vector...so for your problem, the +/- indicates the direction is all, since there are no components, it's just in one direction).

 ohhh Thnxxx :D