- #1

- 22

- 0

## Homework Statement

In an engine, a piston oscillates with simple harmonic motion so that its position varies according to the following expression, where x is in centimeters and t is in seconds.

x = (7.00 cm) cos(4t + π/6)

At t = 0, what is its velocity?

## Homework Equations

v(t) = -A sin(ωt + ϕ)

## The Attempt at a Solution

It first asked me to find the position so I did that easily by plugging in for time and getting an answer. And to get velocity I just had to take the derivative of the initial function and then plug in once again. However, when I do this I do not get the correct answer and I can't figure out why.

The expression should read

v(t) = -7.00 cm sin (4(0) + π/6)

This basicaly breaks down to -7.00 * 1/2 right?

When I do this I get -3.5 cm/s and it says my answer is off by more than 10%. No idea what I am doing wrong.