Question

what is the total mechanical energy of a 3 kg object traveling at 7 m/s if its potential energy is 42 j? (1 point) 115.5 j 247.8 j 31.5 j 73.5 j

Explanation:

Step1: Calculate kinetic energy

The formula for kinetic energy \(K.E.=\frac{1}{2}mv^{2}\). Given \(m = 3\space kg\) and \(v=7\space m/s\), then \(K.E.=\frac{1}{2}\times3\times7^{2}=\frac{1}{2}\times3\times49 = 73.5\space J\)

Step2: Calculate total mechanical energy

The formula for total mechanical energy \(E = K.E.+P.E.\). Given \(P.E. = 42\space J\) and \(K.E.=73.5\space J\), then \(E=73.5 + 42=115.5\space J\)

Answer:

115.5 J