In an engine, a piston oscillates with simple harmonic motion so that its position varies according to the expression

x = 4.7 cos ( 4t + π/6 )

where x is in centimeters and t is in seconds. Find the period of the motion.

when 4 t = 2 pi we have gone around the circle from t = 0

so
4 T = 2 pi

T = 2 pi / 4 = pi/2

To find the period of the motion, we need to identify the coefficient in front of the variable 't' inside the cosine function.

In the given expression, x = 4.7 cos(4t + π/6), the coefficient in front of 't' is 4.

The formula to calculate the period of simple harmonic motion is given by:

T = (2π) / ω,

where T is the period and ω is the angular frequency.

The angular frequency is determined by the coefficient in front of 't' in the function. In this case, it is 4.

Now, we can calculate the period:

T = (2π) / 4,
T = π / 2.

Hence, the period of the simple harmonic motion is π/2 seconds.