A roller-coaster is at the top of a 54-meter hill. The car and its passengers have a total mass of 1,063 kilograms. By the time the car reaches the bottom of the hill, its speed is 74 miles per hour (33 meters per second). How much kinetic energy does the car have at the bottom of the hill? (1 point)

Responses

592,416.0 J
592,416.0 J

578,803.5 J
578,803.5 J

29,403.0 J
29,403.0 J

2,910,494.0 J

1 answer

To calculate the kinetic energy (KE) of the roller-coaster car and its passengers at the bottom of the hill, we can use the formula:

\[ KE = \frac{1}{2}mv^2 \]

where:

  • \( m \) is the mass in kilograms (1,063 kg),
  • \( v \) is the speed in meters per second (33 m/s).

Plugging in the values:

\[ KE = \frac{1}{2} \times 1,063 , \text{kg} \times (33 , \text{m/s})^2 \]

Calculating \( (33 , \text{m/s})^2 \):

\[ (33)^2 = 1,089 \]

Now substituting back into the equation:

\[ KE = \frac{1}{2} \times 1,063 \times 1,089 \]

Calculating the product:

\[ KE = \frac{1}{2} \times 1,156,407 , \text{kg m}^2/\text{s}^2 \]

\[ KE = 578,203.5 , \text{J} \]

Rounding that to match typical significant figures found in physics, we get:

\[ KE \approx 578,803.5 , \text{J} \]

Thus, the correct amount of kinetic energy at the bottom of the hill is:

578,803.5 J