An environmental agency wants to evaluate the effectiveness of rain gardens in reducing the impact of urban runoff from an impervious parking lot and from the roof of the building. The parking lot is slightly sloped so the rainwater flows toward the gardens. The runoff from the roof is collected by various downspouts and directed toward the gardens. Scientists at the agency plan to monitor the effectiveness by measuring the water quality of the storm water as it moves through the gardens during and after storm events. Which of the following would be the best measure to use to determine the effectiveness of the rain gardens in reducing the impact of urban runoff?
A) The size and shape of the rain gardens
B) The intensity and duration of the storm event
C) The speed and volume of the water exiting the gardens
D) The temperature of the parking lot and the roof

If your workout exceeds an hour you should substitute "a sports drink" for water.hope my answer has you : )

Answer: a charge of -1.0  × 10⁻⁴ c must be placed  at x = 26 m.the sign of the charge will be the same sign as the  -4.0  µc charge.======electricstatic force between two point charges  is given by    where k is coulomb's constant,  8.99×10⁹  n·m²/c², q₁ and q₂ are the point charges, and r is the distance between the two point charges.assign positive to q₁let q₁ =  6.0 µc, q₂ = -4.0  µc, q₀ represent the charge at the origin, and q₃ represent this new charge to place.the charge at the origin q₀ would experience the following force f₀₁ from q₁, with r = 6.0 m (note that 1  µc = 10⁻⁶ c)    the force from q₂    the force from q₃    the net force on the origin charge, q₀, has to be zero for no electrostatic forcehaving an equation where k and q₀ can be divided out of the equation will allow us to solve for q₃    isolating:     a charge of -1.0  × 10⁻⁴ c must be placed  at x = 26 m.the sign of the charge will be the same as the  -4.0  µc charge

Ithink the answer for this is: an electromagnet is a magnet  with a soft metal core.