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? (Use the 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]\[ PE = m \cdot g \cdot h \][/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]\( 9.8 \, \text{m/s}^2 \)[/tex]),
- [tex]\( h \)[/tex] is the height.

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

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

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

Now, plug in the values:

[tex]\[ m = \frac{235,200 \, \text{J}}{9.8 \, \text{m/s}^2 \times 30 \, \text{m}} \][/tex]

Calculate the denominator first:

[tex]\[ 9.8 \, \text{m/s}^2 \times 30 \, \text{m} = 294 \, \text{m}^2/\text{s}^2 \][/tex]

Now divide the potential energy by this result:

[tex]\[ m = \frac{235,200 \, \text{J}}{294 \, \text{m}^2/\text{s}^2} \][/tex]

[tex]\[ m \approx 800 \, \text{kg} \][/tex]

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