This is a common question among students of engineering mechanics. When should you use sin or cos in a given equation? The answer is actually quite simple.

If you are working with angles in degrees, then you should use sin. However, if you are working with angles in radians, then you should use cos.

This is because sin and cos are inverse functions of each other. This means that when you take the cos of an angle, you are actually finding the sin of the angle in radians.

So, to recap, if you are working with angles in degrees, use sin. If you are working with angles in radians, use cos.

## Other related questions:

### Q: How do you know if an angle is sin or cos in physics?

A: There is no definitive answer to this question since it depends on the specific situation. However, in general, if an angle is associated with a wave function, it is usually sine, and if it is associated with a force, it is usually cosine.

### Q: Why do we use sin Cos Tan in physics?

A: There are many reasons why we use sin, cos, and tan in physics. One reason is that these functions allow us to more easily solve problems involving triangles. For example, if we know the length of one side of a right triangle and the angle adjacent to that side, we can use the cosine function to find the length of the other side.

### Q: Why do we use sin in torque?

A: There are a few reasons why we might use sin in torque calculations. One reason is that sin is a function that describes the relationship between the angle of a force and the amount of torque that force produces. By using sin in our calculations, we can more accurately determine the amount of torque that a force will produce. Additionally, sin is often used in calculations because it is a relatively simple function to work with, and it can be easily inverted (which means that we can solve for the angle of a force if we know the amount of torque it produces).

### Q: Why is cos used in dot product?

A: The dot product is a way of multiplying two vectors together to produce a scalar result. The cosine function is used in the dot product because it represents the angle between two vectors.