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question 7
the kinetic energy of an 1800 - kg truck is 7.2×10⁵ j. what is the speed of the truck?
25 m/s
17 m/s
21 m/s
33 m/s
28 m/s

Explanation:

Step1: Recall the kinetic energy formula

The formula for kinetic energy is \(K = \frac{1}{2}mv^{2}\), where \(K\) is kinetic energy, \(m\) is mass, and \(v\) is speed. We need to solve for \(v\).
First, rearrange the formula for \(v\):

$$v=\sqrt{\frac{2K}{m}}$$

Step2: Substitute the given values

Given \(K = 7.2\times 10^{5}\space J\) and \(m = 1800\space kg\).
Substitute into the formula:

$$v=\sqrt{\frac{2\times7.2\times 10^{5}}{1800}}$$

$$v=\sqrt{\frac{1.44\times 10^{6}}{1800}}$$

$$v=\sqrt{800}$$

$$v = 28.28\approx28\space m/s$$

Answer:

28 m/s