Select the correct answer.

Five marbles roll down a ramp. Each marble reaches the bottom of the ramp at a speed of 3 meters/second. Which marble has the highest kinetic energy at the bottom of the ramp? The table lists the mass of each marble.

\begin{tabular}{|l|l|l|l|l|}
\hline Marble 1 & Marble 2 & Marble 3 & Marble 4 & Marble 5 \\
\hline 10 g & 20 g & 25 g & 40 g & 30 g \\
\hline
\end{tabular}

A. Marble 1
B. Marble 2
C. Marble 3
D. Marble 4
E. Marble 5



Answer :

To determine which marble has the highest kinetic energy at the bottom of the ramp, we need to consider the kinetic energy formula:

[tex]\[ \text{KE} = \frac{1}{2} m v^2 \][/tex]

where:
- [tex]\( \text{KE} \)[/tex] is the kinetic energy,
- [tex]\( m \)[/tex] is the mass in kilograms,
- [tex]\( v \)[/tex] is the velocity in meters per second.

Given the masses of the marbles and their speed of 3 meters/second, we can determine the kinetic energy for each marble.

1. Convert the masses from grams to kilograms:
[tex]\[ \text{Marble 1: } 10\,g = 0.01\,kg \\ \text{Marble 2: } 20\,g = 0.02\,kg \\ \text{Marble 3: } 25\,g = 0.025\,kg \\ \text{Marble 4: } 40\,g = 0.04\,kg \\ \text{Marble 5: } 30\,g = 0.03\,kg \][/tex]

2. Calculate the kinetic energy for each marble:
[tex]\[ \text{KE}_1 = \frac{1}{2} \times 0.01\,kg \times (3\,m/s)^2 = \frac{1}{2} \times 0.01 \times 9 = 0.045\,J \\ \text{KE}_2 = \frac{1}{2} \times 0.02\,kg \times (3\,m/s)^2 = \frac{1}{2} \times 0.02 \times 9 = 0.09\,J \\ \text{KE}_3 = \frac{1}{2} \times 0.025\,kg \times (3\,m/s)^2 = \frac{1}{2} \times 0.025 \times 9 = 0.1125\,J \\ \text{KE}_4 = \frac{1}{2} \times 0.04\,kg \times (3\,m/s)^2 = \frac{1}{2} \times 0.04 \times 9 = 0.18\,J \\ \text{KE}_5 = \frac{1}{2} \times 0.03\,kg \times (3\,m/s)^2 = \frac{1}{2} \times 0.03 \times 9 = 0.135\,J \][/tex]

3. Compare the kinetic energies:
[tex]\[ \text{Marble 1: } 0.045\,J \\ \text{Marble 2: } 0.09\,J \\ \text{Marble 3: } 0.1125\,J \\ \text{Marble 4: } 0.18\,J \\ \text{Marble 5: } 0.135\,J \][/tex]

From the calculations, it’s clear that Marble 4 has the highest kinetic energy of [tex]\( 0.18\,J \)[/tex].

Therefore, the marble with the highest kinetic energy at the bottom of the ramp is:

D. Marble 4