Question

1. calculate the kinetic energy, in j, of a 12.5 - g object moving at a speed of 81.9 m/s.

a. 145 j
b. 0.950 j
c. 41.9 j
d. 41900 j
e. 1450 j

Explanation:

Step1: Convert mass to kg

The formula for kinetic energy is \(KE=\frac{1}{2}mv^{2}\). Given \(m = 12.5\ g\). Since \(1\ kg=1000\ g\), then \(m=\frac{12.5}{1000}=0.0125\ kg\), \(v = 81.9\ m/s\).

Step2: Calculate kinetic energy

Substitute \(m = 0.0125\ kg\) and \(v = 81.9\ m/s\) into the formula \(KE=\frac{1}{2}mv^{2}\).

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Answer:

C. \(41.9\ J\)