# Tutor profile: Eric P.

## Questions

### Subject: Physics

How far will a 500 gram puck slide on ice given that that the coefficient of kinetic friction between ice and the puck is 0.100 and is traveling at 10m/s.

51.0 meters . There should only be 3 sig figs. It is an energy problem. All the initial energy is kinetic friction. It gets converted to frictional energy. So the equation used is 1/2mv^2 = Fd where F is calculated by multiplying the normal force to the coefficient of kinetic friction.

### Subject: Trigonometry

How can you memorize trig functions easier?

Memorize 1 and derive the others. For example memorize that sin^2(x) + cos^2(x) = 1 Divide everything by sin^2(x) gets : 1 + cot^2(x) = csc^2(x) Divide sin^2(x) + cos^2(x) = 1 by cos^2(x) yields : tan^2(x) + 1 = sec^2(x)

### Subject: Chemistry

what is the single replacement chemical reaction that occurs when Aluminum reacts with hydrochloric acid?

2 Al + 6 HCl --> 2 AlCl(3) + 3H(2) (numbers in parenthesis signify numbers that should be in subscript) The Charge of Al as a solid by itself is zero. When it is in aqueous form the charge is a 3+ and since the charge of Cl is 1- the aluminum chloride needs a 3 subscript after the Cl. The charge of H is a 1+ so the HCl is neutral and when the hydrogen is bonded to itself it is a diatomic and the charge is neutral. So the charges of every compound is neutral and the chemical reaction is balanced.

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