A ball has a potential energy of 180 J and a kinetic energy of 0 J. After falling 2m, it has a potential energy of 135J. What is its kinetic energy at this point?
PLEASE ANSWER THIS I'M STUCK!
Assuming energy is conserved, gravitational potential energy and kinetic energy 'swap' during a fall, and the numeric values transfer. I would say the answer is 180 - 135 = 45J
Kinetic energy = 45J
To find the kinetic energy of the ball after falling 2m, we can use the principle of conservation of mechanical energy, which states that the total mechanical energy (sum of kinetic and potential energy) of an object remains constant in the absence of external forces, such as air resistance or friction.
Initially, the ball has a potential energy of 180 J and no kinetic energy, so the total mechanical energy is 180 J. After falling 2m, the potential energy decreases to 135 J. To find the kinetic energy at this point, we need to calculate the difference in potential energy and adjust the total mechanical energy accordingly.
The change in potential energy can be calculated by subtracting the final potential energy from the initial potential energy:
ΔPE = PE_final - PE_initial
ΔPE = 135 J - 180 J
ΔPE = -45 J
Since the total mechanical energy remains constant, the change in potential energy is equal to the change in kinetic energy. Thus, the change in kinetic energy is also -45 J.
To find the kinetic energy at this point, we need to adjust the total mechanical energy by the change in kinetic energy:
Total mechanical energy = Initial kinetic energy + Initial potential energy
Since the initial kinetic energy is 0 J, we can set up the equation:
Total mechanical energy = 0 J + 180 J
Total mechanical energy = 180 J
Now, we can find the kinetic energy at this point:
Total mechanical energy = Final kinetic energy + Final potential energy
Rearranging the equation to solve for the final kinetic energy:
Final kinetic energy = Total mechanical energy - Final potential energy
Final kinetic energy = 180 J - 135 J
Final kinetic energy = 45 J
Therefore, the kinetic energy of the ball after falling 2m is 45 J.