Answer:
ΔL = L0 C ΔT
We need to find C the constant of expansivity
C = ΔL / (L0 ΔT)
C = .96 / (15.04 * 65) = 9.82 * 10^-4 / deg C
1) In the reference frame of one electron: 0.38c
To find the relative velocity of one electron with respect to the other, we must use the following formula:

where
u is the velocity of one electron
v is the velocity of the second electron
c is the speed of light
In this problem:
u = 0.2c
v = -0.2c (since the second electron is moving towards the first one, so in the opposite direction)
Substituting, we find:

2) In the reference frame of the laboratory: -0.2c and +0.2c
In this case, there is no calculation to be done. In fact, we are already given the speed of the two electrons; we are also told that they travel in opposite direction, so their velocities are
+0.2c
-0.2c
Most ultrasound technicians train in an associates degree, but can also get a bachelors degree in the field. There is also certification programs you can go through. Hope this helped!!! :)
Answer: 2.92 s
Explanation:
Given
Mass of ball is 
The initial velocity of the ball is 
Velocity after the rebound is 
Force during the contact is 
We know, change in momentum is Impulse


Thus, the force is applied for 2.92 s