Answer :
The mechanical energy of the object, under the assumption of zero potential energy, is 180 Joules.
To calculate the mechanical energy of a 0.4 kg object moving at 30 m/s, which is the sum of its kinetic and potential energies, we need to consider both forms of energy. The mechanical energy (M.E.) is given by the formula M.E. = Kinetic energy (K.E.) + Potential energy (P.E.)
Given that the object is moving, we can assume that its potential energy is zero since it is not specified. This assumption is reasonable when dealing with objects in motion. Therefore, the calculation of mechanical energy simplifies to M.E. = K.E.
To find the kinetic energy (K.E.) of the object:
The formula for kinetic energy is K.E. = 0.5 * mass * velocity^2.
Substituting the values, K.E. = 0.5 * 0.4 kg * (30 m/s)^2 = 180 J.
Hence, the mechanical energy of the object, considering only its kinetic energy, is 180 Joules.
Complete question may be like this:
"A 0.4 kg object is moving with a velocity of 30 m/s. What is the mechanical energy of the object if it is the sum of its kinetic and potential energies? If the potential energy is not specified, what assumption can we make about it, and how does it affect the calculation of mechanical energy?"
