PhysicsLAB CP Workbook
Action-Reaction #2

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Refer to the following information for the next thirteen questions.

Nellie Newton holds an apple weighing one newton at rest on the palm of her hand. The force vectors shown are the forces that act on the apple.
 
 
To say the weight of the apple is 1 N is to say that a downward gravitational force of 1 N is exerted on the apple by
 
Nellie's hand supports the apple with normal force N, which acts in a direction opposite to W. We can say N
 
Since the apple is at rest, the net force on the apple is
 
N is equal and opposite to W. We ____ say that N and W comprise an action-reaction pair.
 
The reason is because action and reaction always
 
and here we see N and W
 
In accord with the rule, "If ACTION is A acting on B, then REACTION is B acting on A," if we say action is the earth pulling down on the apple, reaction is

 
To repeat for emphasis, we see that N and W are equal and opposite to each other

 
Another pair of forces is N [shown] and the downward force of the apple against Nellie's hand [not shown]. This force pair ____ an action-reaction pair.
 
Suppose Nellie now pushes upward on the apple with a force of 2 N. The apple
 
and compared to W, the magnitude of N is


 
Once the apple leaves Nellie's hand, N is
 
and the net force on the apple is
 



 
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