W=f*d = 5000N * 10 stories * each 4m = 200 000 J
Assume that energy losses (due to aerodynamic resistance or bearing friction are negligible).
At the highest point, the pendulum has its maximum potential energy (PE) and zero kinetic energy (KE). The total energy is equal to the PE = 141 J.
At the lowest point, the pendulum has its maximum KE, and zero PE. The total energy is equal to the KE.
Because energy is preserved, therefore
KE at the lowest point = PE at the highest point = 141 J.
Answer: 141 J
Answer:
Given that
speed u=4*10^6 m/s
electric field E=4*10^3 N/c
distance b/w the plates d=2 cm
basing on the concept of the electrostatices
now we find the acceleration b/w the plates to find the horizontal distance traveled by the electron when it hits the plate.
acceleration a=qE/m=
=
m/s
now we find the horizontal distance traveled by electrons hit the plates
horizontal distance
![X=u[2y/a]^{1/2}](https://tex.z-dn.net/?f=X%3Du%5B2y%2Fa%5D%5E%7B1%2F2%7D)
=![4*10^6[2*2*10^{-2}/7*10^{14}]^{1/2}](https://tex.z-dn.net/?f=4%2A10%5E6%5B2%2A2%2A10%5E%7B-2%7D%2F7%2A10%5E%7B14%7D%5D%5E%7B1%2F2%7D)
=
= 3 cm