College

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. [tex]$7,840 \, \text{kg}$[/tex]
C. 8,000 kg
D. [tex]$78,400 \, \text{kg}$[/tex]

Answer :

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

[tex]\[ PE = m \cdot g \cdot h \][/tex]

where:
- [tex]\( PE \)[/tex] is the potential energy,
- [tex]\( m \)[/tex] is the mass,
- [tex]\( g \)[/tex] is the acceleration due to gravity (approximately [tex]\( 9.81 \, \text{m/s}^2 \)[/tex]),
- [tex]\( h \)[/tex] is the height.

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]\( 9.81 \, \text{m/s}^2 \)[/tex].

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

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

Substitute the given values into the formula:

[tex]\[ m = \frac{235,200}{9.81 \cdot 30} \][/tex]

[tex]\[ m = \frac{235,200}{294.3} \][/tex]

[tex]\[ m \approx 799.18 \][/tex]

Therefore, the mass of the roller coaster is approximately [tex]\( 799.18 \, \text{kg} \)[/tex]. The closest answer to this value from the provided options is [tex]\( 800 \, \text{kg} \)[/tex].