A20 kg child is on a swing that hangs from 2.4-m-long chains. part a what is her maximum speed if she swings out to a 44 ∘ angle?

Answer;

= 3.63 m/s

Explanation;The speed reaches its maximum V when the swing arrives at its vertical position. At that very moment its kinetic energy is  mV^2/2.  In the initial position the potential energy is mgL(1-cosA), where L is the length, and  A is the maximum angle. Considering that the potential energy is zero in the vertical position. Conservation of energy requires that ;

mV^2/2=mgL(1-cosA)  

Thus;  

V=sqrt[(2gL(1-cosA)]

 = √[2 × 9.8 × 2.4 × (1 - cos 44)]

 = √ 13.202

= 3.63 m/s

stands for electromotive force and it is measured in volts. despite its name, it is not actually the force in the sense of being a "pushing" or "pulling" (not measured in newtons).an equation that relates emf,  ℰ,  to a battery's terminal voltage, v, current, i, and internal resistance, r, is    ℰ = v + irin this case, the emf can be interpreted as a voltage—a difference in electric potential.i would not say that it would be considered an energy. if emf can be defined as the energy/work per a unit charge from a battery or other electric source, then it is not strictly energy.