a person on a bike (m=90 kg) is travelling 4 m/s at the top of a 2 m hill. what is the bikers total energy?
A) 720 J
B) 1994 J
C) 2484 J
D) 1764 J
I think it’s 720 J but I’m not sure. Could someone tell me if I’m right?
pls
kinetic energy ... 1/2 m v^2 = 1/2 * 90 * 4^2
gravitational potential energy ... m g h = 90 * 9.8 * 2
add the two energies
Thank you!
To calculate the biker's total energy, we need to consider both their potential energy and kinetic energy at the top of the hill.
1. Potential energy (PE):
At the top of the hill, the biker has gravitational potential energy due to their height above the ground. The formula for potential energy is: PE = m * g * h, where m is the mass of the biker, g is the acceleration due to gravity, and h is the height.
Given:
Mass of the biker (m) = 90 kg
Height of the hill (h) = 2 m
Acceleration due to gravity (g) = 9.8 m/s^2
Plugging in these values, we can calculate the potential energy:
PE = 90 kg * 9.8 m/s^2 * 2 m = 1764 J
2. Kinetic energy (KE):
The biker also has kinetic energy due to their motion. The formula for kinetic energy is: KE = 0.5 * m * v^2, where m is the mass of the biker and v is the velocity.
Given:
Mass of the biker (m) = 90 kg
Velocity (v) = 4 m/s
Plugging in these values, we can calculate the kinetic energy:
KE = 0.5 * 90 kg * (4 m/s)^2 = 720 J
3. Total energy:
To find the total energy, we need to add the potential energy and kinetic energy together:
Total energy = Potential energy + Kinetic energy = 1764 J + 720 J = 2484 J
Therefore, the biker's total energy is 2484 J. So, the correct option is C) 2484 J.