Final answer:
To find the maximum velocity of the roller coaster car at the lowest point, the gravitational potential energy at the top is equated with the kinetic energy at the bottom, and by solving the equations, the maximum velocity is approximately 22 m/s.
Step-by-step explanation:
The student's question is about finding the maximum velocity of a roller coaster car at the lowest point of the track, given that its mass is 250 kg and the gravitational potential energy (GPE) at the top is 61,250 J. According to the conservation of energy, the GPE at the top of the hill will convert into kinetic energy (KE) at the bottom of the hill if we neglect energy losses due to friction. The formula for KE is KE = ½ mv², where m is mass and v is velocity. We are given that GPE = mgh, where g is the acceleration due to gravity (9.8 m/s²) and h is the height (25 m). Because the total mechanical energy is conserved, the GPE at the top will be equal to the KE at the bottom; therefore, we can set them equal to each other and solve for v:
GPE = KE
mg(h) = ½ mv²
61,250 J = ½ × 250 kg × v²
By simplifying this equation and solving for v, we find that:
61,250 J = 125 kg × v²
490 = v²
v ≈ √490 ≈ 22.1 m/s
The maximum velocity of the roller coaster car at the lowest point of the track is approximately 22 m/s, which rounds to 22 m/s as the nearest whole number.