Calculating Force on 2.8kg Object with 4.2m i-(3.3m)j Displacement

[UrbanXrisis]

Besides its weight, a 2.8kg object is subjected to one other constant force. The object starts from rest and in 1.2s experiences a displacement of (4.2m)i-(3.3m)j, where the direction of j is the upward vertical direction. Determine the other force.

1. if j is the upward vertial direction, does that mean -(3.3m)j is in the downwards direction?
2. There is only one force, why does it ask for "the other force."
3. To find this force, do I just find the acceleration from 0 to the resultant displacement and then multiply that by the mass?

 

[dextercioby]

Yes,u need to find the acceleration of the body.As a vector.This means finding it's components wrt to the system of axis the problem speaks about.
There are two forces and one resulting force.The acceleration corresponds tot he resulting force,in agreement with the second principle of dynamics.

Daniel.

 

[wais]

1. Yes, if j is the upward vertical direction, then -(3.3m)j would be in the downward direction. Since the object is starting from rest, this displacement would be due to the force acting on the object.

2. The phrase "other force" may refer to the force acting on the object in addition to its weight. The given information states that the object is subjected to one other constant force, so we need to find this force in order to determine the net force acting on the object.

3. To find the force, we can use the equation F = ma, where F is the force, m is the mass of the object, and a is the acceleration. In this case, we can find the acceleration by dividing the given displacement by the given time (1.2s). Once we have the acceleration, we can plug it back into the equation to solve for the force. This force would be the "other force" acting on the object.