Answer:
1/2 Hz
Explanation:
A simple harmonic motion has an equation in the form of
where A is the amplitude, 
is the angular frequency and 
is the initial phase.
Since our body has an equation of x = 5cos(π t + π/3) we can equate 
and solve for frequency f
f = 1/2 Hz
None of the choices is an appropriate response.
There's no such thing as the temperature of a molecule. Temperature and
pressure are both outside-world manifestations of the energy the molecules
have. But on the molecular level, what it is is the kinetic energy with which
they're all scurrying around.
When the fuel/air mixture is compressed during the compression stroke,
the temperature is raised to the flash point of the mixture. The work done
during the compression pumps energy into the molecules, their kinetic
energy increases, and they begin scurrying around fast enough so that
when they collide, they're able to stick together, form a new molecule,
and release some of their kinetic energy in the form of heat.
