Question
Q4- EP6) Um guindaste eleva um piano de 250 kg até a altura de 20m/s em relação ao solo em um local onde g= 10m/s^2 Qual é a energia potencial gravitacional do piano nessa posição: a) em relação ao solo? b) em relação a um referencial equidistante entre o piano e solo?
Solution
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Paulo
Mestre · Tutor por 5 anos
Resposta
a) The weight of the piano is also the potential energy of the piano in relation to the altitude where it is elevated by the crane, which is 50,000 joules. b) The potential energy of the piano relative to the midpoint between the piano and the ground is half of that in relation to the ground, i.e. 25,000 joules.
Explicação
This is a standard physics question about gravitational potential energy. Potential energy describes the potential a physical system has to do work due to its positioning or configuration. In this case, the piano being raised by a crane gains potential energy as its height from the ground increases, as does the potential energy to perform work by falling to the ground due to Gravity's pull.Gravitational potential energy is calculated by the formula: PE = m * g * h where PE = potential energy m = mass (in kg)g = gravitational acceleration (in m/s^2)h = height above ground (in m) The question asks you to calculate this potential energy in two different situations. a) Relative to the ground. b) Relative to a reference point equidistant between the ground and the piano, which places the piano at 10m above this reference point. In the latter case, the height h is halved, but the calculation is otherwise the same. Let's work through this.