Help!!! Physics Problem!!!?

Question

1.) A 1.00kg object is observed to have an acceleration of 10.0m/s^2 in a direction 30.0° north of east. The force F2 acting on the object has a magnitude of 5.00N and is directed north. Determine the magnitude and direction of the force F1 acting on the object.

2.) A frictionless plane is 10.0m long and inclined at 35.0° . A sled starts at the bottom with an initial speed of 5.00m/s up to the incline. When it reaches the point at which it momentarily stops, a second sled is released from the top of this incline with an initial speed vf. Both sleds reach the bottom of the incline at the same moment. (a) Determine the distance that the first sled traveled up the incline. (b) Determine the initial speed of the second sled.

Answer 1

1. This is solved using F=m*a and the hypotenuse is equal to the square root sum of the squares.

Looking at each directional component:
in the North direction
5.00=1.00*10*sin(30)
that was a nice check

The East direction is
F1=1*10*cos(30)

2. a) using conservation of energy:
.5*m*v^2=m*g*h
and L*sin(35)=h, so
L=.5*25/(9.81*sin(35))

using F=m*a
sin(35)*g=a along the incline for both sleds
For the first sled that stopped, it reaches the bottom when it once again achieves a speed of 5.00 m/s, so
5=sin(35)*g*t,
where t is the time after the pause that it reaches the bottom.
t=5/(sin(35)*9.81)
The second sled equation of motion is
10=vf*t+.5*sin(35)*t^2
since the second sled must traverse 10 m in the time it took the first sled to return to the bottom. We know t
so
vf=(10-.5*sin(35)*t^2)/t

j