Catching a wave, a 65 kg surfer starts with a speed of 1.3 m/s, drops through a height of 2.10 m, and ends with a speed of 8.2 m/s. How much nonconservative work was done on the surfer?
I have genuinely no idea how to solve this problem.
Initial PE+change in PE-KE=nonconservative work.
If you have no idea how to do these, you need a tutor.
At the college bookstore, or BarnesNoble, Schaum's Outline Series College Physics (or similar in the series) are very excellent on problems.
1) my teacher is really bad.
2) Is delta potential energy = mgvf - mgvi
initial energy= 1/2*65*1.3^2
added energy= 65*9.8*2.1
add those.
subtract finalke=1/2 65*8.2^2
the remainer is the work done.
Thank you, I understand that now.
To find the amount of nonconservative work done on the surfer, you will need to calculate the change in the mechanical energy of the surfer during the wave ride. This change in mechanical energy is equal to the nonconservative work done on the surfer.
The mechanical energy of the surfer can be divided into two components: kinetic energy (KE) and gravitational potential energy (PE). The formula for kinetic energy is KE = (1/2)mv^2, where m is the mass of the surfer and v is the velocity. The formula for gravitational potential energy is PE = mgh, where m is the mass, g is the acceleration due to gravity, and h is the height.
In this problem, the surfer starts with an initial kinetic energy (KE1) due to the initial speed of 1.3 m/s, and an initial potential energy (PE1) due to the height of 2.10 m. The final kinetic energy (KE2) is determined by the final speed of 8.2 m/s, and the final potential energy (PE2) is zero since the surfer is at sea level.
The change in kinetic energy (ΔKE) is given by ΔKE = KE2 - KE1, and the change in potential energy (ΔPE) is given by ΔPE = PE2 - PE1.
Once you have found the change in kinetic energy and potential energy, you can find the change in mechanical energy (ΔE) by summing these values: ΔE = ΔKE + ΔPE.
However, since we are interested in the nonconservative work done on the surfer, we assume no other external forces, such as friction, are acting on the surfer. Therefore, the change in mechanical energy (ΔE) is equal to the nonconservative work (Wnc): Wnc = ΔE.
Now let's plug in the given values and calculate:
Mass of the surfer (m) = 65 kg
Initial speed (v1) = 1.3 m/s
Height (h) = 2.10 m
Final speed (v2) = 8.2 m/s
Acceleration due to gravity (g) = 9.8 m/s^2
Calculate the initial and final kinetic energy:
KE1 = (1/2)mv1^2
KE2 = (1/2)mv2^2
Calculate the initial and final potential energy:
PE1 = mgh
PE2 = 0 (since the surfer is at sea level)
Calculate the change in kinetic energy (ΔKE):
ΔKE = KE2 - KE1
Calculate the change in potential energy (ΔPE):
ΔPE = PE2 - PE1
Finally, calculate the nonconservative work done on the surfer:
Wnc = ΔE = ΔKE + ΔPE
By following these steps, you can obtain the value for the nonconservative work done on the surfer.