A 500-kg roller coaster car travels with some initial velocity along a track that is 5 m above the ground. The car goes down a small hill and then coasts back up a higher hill. The second hill is 12 m above the ground. What must the initial velocity of the car be for the car to be going 3 m/s at the top of the second hill?
A.3.0 m/s
B.5.0 m/s
C.9.8 m/s
D.12 m/s

The independent variable would be the fertilizer as it is what the dependent variable (the growth of grass) depends on.

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

Answer mechanical energy;