Answer:
<u><em>1000 units for breakeven</em></u>
Explanation:
Let x be the number of units sold at breakeven.
The total sales at the point would be $2x.
Variable costs would be $1x and fixed costs are $1000.
Total costs are = $1x + $1000
At breakeven: Sales = Costs
Sales =m Costs
$2x = $1x + $1000
$1x = $1000
x = 1000 units.
At 1000 units the sales are equal to the costs ("breakeven").
Answer:

Explanation:
According to the free-body diagram of the system, we have:

So, we can solve for T from (1):

Replacing (3) in (2):

The electric force (
) is given by the Coulomb's law. Recall that the charge q is the same in both spheres:

According to pythagoras theorem, the distance of separation (r) of the spheres are given by:

Finally, we replace (5) in (4) and solving for q:

Answer:
-4.0 N
Explanation:
Since the force of friction is the only force acting on the box, according to Newton's second law its magnitude must be equal to the product between mass (m) and acceleration (a):
(1)
We can find the mass of the box from its weight: in fact, since the weight is W = 50.0 N, its mass will be

And we can fidn the acceleration by using the formula:

where
v = 0 is the final velocity
u = 1.75 m/s is the initial velocity
t = 2.25 s is the time the box needs to stop
Substituting, we find

(the acceleration is negative since it is opposite to the motion, so it is a deceleration)
Therefore, substituting into eq.(1) we find the force of friction:

Where the negative sign means the direction of the force is opposite to the motion of the box.