Answer:
(d) A strong electron-phonon interaction
Explanation:
Superconductivity -
The phenomenon of superconductivity is due to the attractive force between electrons from the exchange of the phonons that cause the bound pair of electrons known as cooper pairs .
A strong electron -phonon intercation is suitable condition for superconductivity and high resistance .
Answer:
1) No, the car does not travel at constant speed.
2) V = 9 ft/s
3) No, the car does not travel at constant speed.
4) V = 5.9 ft/s
Explanation:
In order to know if the car is traveling at constant speed we need to derive the given formula. That way we get speed as a function of time:
V(t) = 2*t + 2 Since the speed depends on time, the speed is not constant at any time.
For the average speed we evaluate the formula for t=2 and t=5:
d(2) = 8 ft and d(5) = 35 ft
Again, for the average speed we evaluate the formula for t=1.8 and t=2.1:
d(1.8) = 6.84 ft and d(2.1) = 8.61 ft
Answer:
f=-1380N
Explanation:
A karate master wants to break a board by hitting the board swiftly with his hand. The master's hand has a mass of 0.30 kg, and as it strikes the board, his hand has a velocity of 23.3 m/s. The master contacts the board for 0.0050 seconds
.the concluding part to the question should be
What is the impact force (impulse) on the board?
solution
from the Newton's second law of motion which states that
the rate of change in momentum is directly proportional to the force applied
f=m(v-u)/t
f=0.3(0-23.3)/0.005
f=-1380N
f=force impact
m=mass of the karates master's hand
t=time for the impact
v=0m/s final velocity
u=initial velocity
The formula v=fλ can be used here.
326=2500*λ
Note the 2500 as 2.5kHz is 2.5 thousand Hz.
λ = 326/2500
= 0.1304m = 0.130m
F = ma
F = (1000 kg)•(5 m/s^2)
F = 5000 N
