High School

A roller coaster with a potential energy of [tex]$235,200 J$[/tex] sits at the top of a 30 m high hill. What is the mass of the roller coaster?

(Formula: [tex]PE = mgh[/tex])

A. 800 kg
B. 7,840 kg
C. 8,000 kg
D. 78,400 kg

Answer :

Sure, let's solve the problem step-by-step!

We are given:
- Potential energy ([tex]\(PE\)[/tex]) = [tex]\(235,200 \, \text{J}\)[/tex]
- Height ([tex]\(h\)[/tex]) = [tex]\(30 \, \text{m}\)[/tex]
- Acceleration due to gravity ([tex]\(g\)[/tex]) = [tex]\(9.8 \, \text{m/s}^2\)[/tex]

We need to find the mass ([tex]\(m\)[/tex]) of the roller coaster, using the formula:
[tex]\[ PE = mgh \][/tex]

First, we will rearrange the formula to solve for mass ([tex]\(m\)[/tex]):
[tex]\[ m = \frac{PE}{gh} \][/tex]

Now, we will substitute the given values into the formula:
[tex]\[ m = \frac{235,200 \, \text{J}}{9.8 \, \text{m/s}^2 \times 30 \, \text{m}} \][/tex]

Next, we calculate the denominator:
[tex]\[ 9.8 \times 30 = 294 \][/tex]

Then we divide the potential energy by this result:
[tex]\[ m = \frac{235,200}{294} \][/tex]

Performing the division gives:
[tex]\[ m \approx 800 \, \text{kg} \][/tex]

So, the mass of the roller coaster is approximately [tex]\(800 \, \text{kg}\)[/tex].

Therefore, the correct answer is:

[tex]\[ \boxed{800 \, \text{kg}} \][/tex]