3. Two charged boxes are 4 meters apart from each other. The blue box has a charge of +0.000337
C and is attracting the red box with a force of 626 Newtons. Determine charge of the red box.
Remember to indicate if it is positive or negative.
0.0033 C

Charge on the red box is -0.0033 C as it is attracting the blue box

Explanation:

As we know that two boxes are attracting each other

So here we can say that two boxes will have opposite charges

So as we know that electrostatic force between two charges is given as

here we have

here we know that

r = 4 m

F = 626 N

pretty sure it's false

there are no contact forces mentioned on the list of choices that you've provided.