# Tutor profile: Alyssa S.

## Questions

### Subject: Chemistry

Balance the following equation: Cr(OH)3 + HClO4 -> Cr(ClO4)3 + H2O

Cr(OH)3 + 3HClO4 -> Cr(ClO4)3 + 3H2O

### Subject: Algebra

Solve the following system of equations: y + 4x = 8 3x + 2y = 7

y + 4x = 8 3x + 2y = 7 to solve multiply the first equation by -2, this will cancel out the y's when you add the two equations together -2 * (y + 4x = 8) 3x + 2y = 7 -2y + -8x = -16 3x + 2y = 7 Add together -2y + -8x = -16 + 3x + 2y = 7 = -5x = - 9 Solve for x: x= 9/5 using first equation to solve for y y= 8-4x= 8-(4*9/5) y= 40/5 - 36/5 = 4/5 x= 9/5 y = 4/5

### Subject: Physics

An observation deck of a tall skyscraper is 370 m above the street. If you drop a penny from the observation deck, how long will it take the penny to free fall from the deck to the street below?

For this we use the equation y = 1/2*a*t^2 + vi*t + yi Where y is the vertical position and yi is the initial vertical position. A is acceleration, and t is time. Since the object is falling the final height is 0 meters, the initial height is 370 m, and the acceleration is gravity or -9.81 m/s^2. Since the object is dropped, the initial velocity is 0. 370 = 1/2(-9.81)t^2 t = sqrt(370/4.9) = 8.69 s t = 8.69 s

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