High School

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

where:
- [tex]\( PE \)[/tex] is the potential energy, which is [tex]\( 235,200 \)[/tex] Joules in this case.
- [tex]\( g \)[/tex] is the acceleration due to gravity, approximately [tex]\( 9.81 \, \text{m/s}^2 \)[/tex].
- [tex]\( h \)[/tex] is the height, which is [tex]\( 30 \)[/tex] meters.
- [tex]\( m \)[/tex] is the mass, which we need to find.

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

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

Now, substituting the values we have:

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

Carrying out the division gives:

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

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