Newton's Laws - Mission NL5 Detailed Help

The diagrams below represent forces acting on an object. The size of the arrow represents the magnitude of the force.
 
A 5.0 kg flying squirrel is gliding vertically from a tree to the ground at constant velocity. Consider air resistance.



 
Often times, success in physics demands that you have the proper approach - a good game plan. A good game plan for this question would be to:
 
  • First, identify if the forces are balanced or unbalanced; and if unbalanced, determine the direction of the unbalanced force (see Think About It section below). This will allow you to eliminate several choices from among the ten diagrams.
  • Second, use your understanding of the various force types to determine if there is a force in each direction - up, down, right, left. This requires that you have a good understanding of the different types of forces and when they are present and absent (use the link in the Hot Link section if necessary). This second step allows you to reduce the number of choices to one.


 
If an object is moving with a constant velocity, then the individual forces acting upon it are balanced. Whichever force diagram you choose, make sure that it is a diagram representing a balance of forces. The up force arrow and the down force arrow should be the same size. And if there are horizontal force arrows, the right arrow should be the same size as the left arrow.


 
A physics question often contains a short phrase which might seem a bit peculiar but serves to provide a hint or clue that might steer you in the right direction. In this question, the clues are the words "gliding" and "vertically". Including these words in the question warns the student that there is no forward propulsion force on the squirrel that results from the use of the wings. (In fact, so-called flying squirrels really can't use their wings at all; they simply glide from tree to tree or tree to ground using their wings as parachute-like devices.) Thus, do not select a diagram with a horizontal force.