College

A roller coaster with a potential energy of [tex]$235,200 \, \text{J}$[/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 :

To find the mass of the roller coaster, we can use the formula for potential energy:

[tex]\[ \text{Potential Energy (PE)} = m \times g \times h \][/tex]

where:
- [tex]\( PE \)[/tex] is the potential energy (235,200 Joules),
- [tex]\( m \)[/tex] is the mass in kilograms,
- [tex]\( g \)[/tex] is the acceleration due to gravity (approximately 9.81 m/s² on Earth),
- [tex]\( h \)[/tex] is the height (30 meters).

We need to rearrange the formula to solve for mass ([tex]\( m \)[/tex]):

[tex]\[ m = \frac{PE}{g \times h} \][/tex]

Now we can plug in the values:

[tex]\[ m = \frac{235,200 \, \text{J}}{9.81 \, \text{m/s}^2 \times 30 \, \text{m}} \][/tex]

Calculating this gives us the mass:

[tex]\[ m \approx 799.18 \, \text{kg} \][/tex]

Since the question is asking for the mass and provides multiple choices, we can see that the closest correct option is [tex]\( 800 \, \text{kg} \)[/tex]. Therefore, the mass of the roller coaster is approximately [tex]\( 800 \, \text{kg} \)[/tex].