What is the kinetic energy of a toy truck with a mass of 0.75 kg and a velocity of 4 m/s? (Formula: $K E=\frac{1}{2} m v^2$ )
The kinetic energy (\(KE\)) of an object is a measure of the energy it possesses due to its motion. The formula given is \(KE = \frac{1}{2}mv^2\), where \(m\) represents the mass of the object and \(v\) represents its velocity. In this problem, we are given:
Our goal is to find the kinetic energy by substituting these values into the formula.
To calculate the kinetic energy, we substitute the known values into the equation:
\[KE = \frac{1}{2} \times (0.75 \text{ kg}) \times (4 \text{ m/s})^2\]
First, calculate the square of the velocity:
\[4^2 = 16 \text{ m}^2/\text{s}^2\]
Next, multiply the mass by the square of the velocity:
\[0.75 \times 16 = 12\]
Finally, multiply this result by \(\frac{1}{2}\):
\[KE = 0.5 \times 12 = 6 \text{ J}\]
The kinetic energy of the toy truck is \(6 \text{ J}\). Comparing this result to the given options, we find that the correct choice is the second one.
Kinetic energy calculations are fundamental in engineering and physics, helping us understand how moving objects interact with their environment. For instance, when designing safety features for toy cars or even real vehicles, engineers calculate the kinetic energy to determine the impact force in a collision. By knowing the mass and speed of an object, we can predict how much work it can perform or the damage it might cause, making this a crucial concept for safety and mechanical design.