Question

The position of a 50 g oscillating mass is given by x(t)=(2.0cm)cos(10t−π/4), where t is in s. If necessary, round your answers to three significant figures. Determine:
the amplitude
2cm
the period
.628s
the spring constant
5N/m
the phase constant
-.785rad
the initial coordinate of the mass
1.41cm
the initial velocity
14.1 cm/s
maximum speed 20 cm/s
what's the total energy?

Answer 1

I think that total energy is the sum of kinetic energy plus potential energy, nevertheless when the speed of oscillating mass is at its maximum, that potential energy is zero, so total energy will be equals to kinetic energy, namely:
\[E=\frac{ 1 }{ 2 }m*v ^{2}=10,000 ergs\]