Pulley on inclined plane problem

[gdhillon]

Q:Two blocks are tied together on an incline The first box is on a 30 degree incline with he horizontal and is 1 KG, the wire from it runs over a pulley that goes to a mass of 2KG . If both the pulley and the incline are frictionless:
a) What is the acceleration of the 1.0 kg block up the incline?
b) What is the tension in the string joining the two blocks.

I first found the FG of the 1KG block and from that used sohcahtoa to get my normal force and my fapp (-9.8sin30) negative because it is 'wanting' to go down the incline away from the 2kg mass. For a) I used Ʃf=ma, 19.6-(9.8sin30)=3a acceleration is 4.9m/s^2
for b) I used Ʃf=ma and had T-19.6=2(4.9) and got tension=29N

 

[PhanthomJay]

Q:Two blocks are tied together on an incline The first box is on a 30 degree incline with he horizontal and is 1 KG, the wire from it runs over a pulley that goes to a mass of 2KG . If both the pulley and the incline are frictionless:
a) What is the acceleration of the 1.0 kg block up the incline?
b) What is the tension in the string joining the two blocks.

I first found the FG of the 1KG block and from that used sohcahtoa to get my normal force and my fapp (-9.8sin30) negative because it is 'wanting' to go down the incline away from the 2kg mass.

gravity wants to pull it down, but the tension wants to pull it up. Tension wins.

For a) I used Ʃf=ma, 19.6-(9.8sin30)=3a acceleration is 4.9m/s^2

yes, what direction?

for b) I used Ʃf=ma and had T-19.6=2(4.9) and got tension=29N

No. In what direction is the acceleration of the 2 kg block?