1) Acceleration of the sled
The acceleration of the sled is given by the net force acting in the direction parallel to the incline. There are two forces acting along this direction: the component of the weight parallel to the ramp (downward) and the friction (upward). Therefore, the net force acting in this direction is
And the acceleration is given by Newton's second law:
2) Normal force
The normal force acting on the sled is equal to the component of the weight perpendicular to the incline, therefore:
Answer:
Toward the north, 300 N
Explanation:
Consider the upward direction as positive and downward direction as negative.
Given:
Mass of the balloon is, 
Lift force on the balloon in the upward direction is, 
Take acceleration due to gravity as 10 N/kg.
Now, weight of the balloon acting downward is given as the product of its mass and acceleration due to gravity. Therefore,
Weight is, 
Now, net force is given as the vector sum of both the forces.
The upward direction is the direction of North. So, the net force acting on the balloon is 300 N towards North.
