# Trig Review for Physics - Common Math Tools - Physics 101, AP Physics 1 Review with Physics Girl | Summary and Q&A

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September 10, 2020
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Physics Girl
Trig Review for Physics - Common Math Tools - Physics 101, AP Physics 1 Review with Physics Girl

## TL;DR

This video provides a refresher on trigonometry, focusing on sines, cosines, and vectors, and how they are used in physics.

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### Q: What is a vector and how is it different from a scalar?

A vector is a measurement that has both magnitude and direction, while a scalar only has magnitude. For example, velocity is a vector quantity as it includes both speed and direction, while speed is a scalar quantity.

### Q: How are similar triangles used in trigonometry?

Similar triangles have the same angles but different dimensions. By comparing the ratios of sides in similar triangles, we can find trigonometric ratios (sine, cosine, tangent) that are independent of the triangle's size.

### Q: How can trigonometry be applied to vectors in physics?

Trigonometry is used to break down vectors into perpendicular components. For example, using trigonometric ratios, we can calculate the speed of an object in different directions or resolve a force vector into its horizontal and vertical components.

### Q: Why is it useful to memorize the sine and cosine of common angles?

Memorizing the sine and cosine of common angles makes solving trigonometric problems quicker and easier. These common angles (0, 30, 45, 60, and 90 degrees) have predictable ratios, which can be useful in various physics and engineering applications.

## Summary & Key Takeaways

• The video begins by introducing vectors as representations of measurements with magnitude and direction.

• It then explains how right triangles are used to define trigonometry functions, with the terms sine, cosine, and tangent.

• The video demonstrates how to use trigonometric ratios to solve problems involving vectors in physics, such as calculating speed and force in different directions.