Question

test information
description
instructions from the list of choices, select the one best answer.
multiple attempts not allowed. this test can only be taken once.
force completion this test can be saved and resumed later.
your answers are saved automatically.
question completion status:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
moving to another question will save this response. question 2 of 22
question 2
4 points save answer
two cars have the same mass, but the red car has twice the speed of the blue car. we then know that the red car has ___ kinetic energy as the blue car.
twice as much
one - half as much
four times as much
one - fourth as much

Explanation:

Step1: Write the kinetic energy formula

The formula for kinetic energy is \(K = \frac{1}{2}mv^{2}\), where \(m\) is mass and \(v\) is speed.

Step2: Let the speed of the blue car be \(v\)

Let the speed of the blue car be \(v\), then the speed of the red car is \(2v\). The mass of both cars is \(m\) (since they have the same mass).
The kinetic energy of the blue car \(K_{blue}=\frac{1}{2}mv^{2}\).
The kinetic energy of the red car \(K_{red}=\frac{1}{2}m(2v)^{2}\).

Step3: Simplify the expression for \(K_{red}\)

$$
LATEXBLOCK0
$$

Since \(K_{blue}=\frac{1}{2}mv^{2}\), we have \(K_{red} = 4K_{blue}\)

Answer:

four times as much