Rob and his sister joan are standing on their apartment balcony. rob throws a ball straight out from the balcony. at the same time, joan drops a ball straight down. both balls reach the ground at the same time. which factor causes the two balls to reach the ground at the same time?

The initial vertical velocities of the balls are the same.

Explanation:

If the air resistance is despised, the phenomena can be expressed by the equation for an accelerated retiling movement:

H = v0*t + gt²/2

Where v0 is the initial velocity, g is the gravity acceleration, and t the time. So, if Rob and Joan drop the ball at the same time and they reach the ground at the same time, the initial vertical velocity of the balls must be the same.

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !

these nuts