# Problem Solving in Physics

by April Atkin
# 1. Conservation of Energy

## 1.1. Energy is usually conserved. Carefully note what kinds of energy you start and finish with and make them equal to each other.

# 2. Conservation of Momentum

## 2.1. Are there any eternal forces?

### 2.1.1. Yes

### 2.1.2. No

2.1.2.1. Great! Momentum is conserved, so final momentum=initial momentum!

## 2.2. Are there any eternal torques?

### 2.2.1. No

2.2.1.1. Great! Angular momentum is conserved! Initial=final.

### 2.2.2. Yes

# 3. Formulas

## 3.1. Check your formula sheet - are there any formulas that have the variables you need to solve this problem?

# 4. Trig Identities

## 4.1. Solving a triangle? Use SOH CAH TOA to find unknown quantities

# 5. Sum of the Forces

## 5.1. Remember, the Sum of the Forces F=ma - if there is no acceleration, there is no net force!

## 5.2. This works for the sum of the torques too. The sum of the torques =I(alpha)