<span>Each of these systems has exactly one degree of freedom and hence only one natural frequency obtained by solving the differential equation describing the respective motions. For the case of the simple pendulum of length L the governing differential equation is d^2x/dt^2 = - gx/L with the natural frequency f = 1/(2π) √(g/L). For the mass-spring system the governing differential equation is m d^2x/dt^2 = - kx (k is the spring constant) with the natural frequency ω = √(k/m). Note that the normal modes are also called resonant modes; the Wikipedia article below solves the problem for a system of two masses and two springs to obtain two normal modes of oscillation.</span>
Explanation :
The heating curve shows how water changes from one state of matter to another based on temperature and the addition or removal of heat over time.
Initially, ice is heated until its temperature reaches 
and changes to liquid state.
From the attached graph it is clear that until 
the temperature will rise steadily. Here, the liquid begins to vaporize. Vaporization is the state of matter at which liquid state changes to the gaseous state.
So, E is the point which shows the gaseous state.
I didn’t know water has calories
Heat engines are less than 100% efficient because absolute zero cannot be reached
B. Transverse Wave this is the correct answer
