College

A roller coaster with a potential energy of 235,200 J 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 solve the problem of finding the mass of the roller coaster, we can use the formula for gravitational potential energy:

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

where:
- [tex]\( PE \)[/tex] is the potential energy, given as 235,200 joules.
- [tex]\( m \)[/tex] is the mass of the roller coaster, which we need to find.
- [tex]\( g \)[/tex] is the gravitational acceleration, usually approximated as 9.81 meters per second squared.
- [tex]\( h \)[/tex] is the height, given as 30 meters.

We need to solve for the mass ([tex]\( m \)[/tex]). Rearranging the formula to find [tex]\( m \)[/tex], we get:

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

Now, plug in the known values:

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

Perform the multiplication in the denominator:

[tex]\[ g \times h = 9.81 \times 30 = 294.3 \][/tex]

Now, divide the potential energy by this result:

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

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

The calculation gives us a mass of approximately 799.18 kilograms. Since this is closest to 800 kilograms in the options provided, the mass of the roller coaster is approximately:

800 kilograms