If the box is moving at constant velocity, net force must be zero, so:
F + fr = 0
fr = -F
<u>fr = -40 N</u>
Answer:

Explanation:
<u>Average Acceleration
</u>
Acceleration is a physical magnitude defined as the change of velocity over time. When we have experimental data, we can compute it by calculating the slope of the line in velocity vs time graph.
Note: <em>We cannot see if the time axis is numbered in increments of 1 second, and we'll assume that.
</em>
When
, the graph shows a value of
When
, the object is at rest, 
We compute the average acceleration as




Answer:
b.
Explanation: I do not know much about this but the answer that i think it is was b.
The cup is acted upon by an unbalanced force which is the cars acceleration, but before it was an object at rest that stayed at rest. This jet propels their body forward.