Question

dec devices in tidal areas
1 - d reflect - a team of engineers is testing a new range of javelins. each javelin has a different mass. a robot is programmed to throw each javelin at the same initial speed so the speed is the control variable. the data is used to calculate the amount of energy in joules (j) in the kinetic stores of the different javelins.

	javelin 1	javelin 2	javelin 3	javelin 4	javelin 5
average speed (m/s)	31.0	31.0	31.0	31.0	31.0
energy (j)	388.0	344.0	295.0	246.0	194.0

1. analyze the graph. which statement most accurately reflects the graph and data, and shows the relationship of the mass of a javelin to its expected energy?

energy vs mass

| c. as the mass of the javelin increases, the expected energy of the javelin decreases in proportion to the change of mass. |

1. if the javelin mass increased to 1.6 kg, how would that affect the data in the table? complete the following sentence.

the energy will ________________ if the ________________ remains the same.

Explanation:

Step1: Analyze the relationship

The kinetic - energy formula is $E = \frac{1}{2}mv^{2}$. Here, the speed $v$ is constant. So, $E$ is directly proportional to $m$ (mass). As $m$ increases, $E$ increases proportionally.

Step2: Answer question 1

Looking at the options for question 1, option a is correct because when mass increases, energy increases in proportion to the change in mass due to the direct - proportional relationship $E=\frac{1}{2}mv^{2}$ with constant $v$.

Step3: Answer question 2

For question 2, since $E=\frac{1}{2}mv^{2}$ and $v$ is constant, if the mass $m$ of the javelin increases to 1.6 kg, the energy will increase because energy is directly proportional to mass when speed is constant.

Answer:

1. a. As the mass of the javelin increases, the expected energy of the javelin increases in proportion to the change of mass.
2. The energy will increase if the average speed remains the same.