Answer:

Explanation:
Given that,
Initial speed of a train, u = 12 m/s
Final speed of a train, v = 9.6 m/s
Time taken, t = 0.8 s
We need to find the average acceleration of the train. We know that the rate of change of velocity is equal to acceleration. So,

So, the average acceleration of the train is equal to
.
Answer:
D.) All people can mate with one another and have children
Explanation:
Given:
The charge q1 = 8.42 nC
The charge q2 = -3.75 nC
The distance between the charges is d = 2.73 cm
To find the electric field strength at the midpoint between the two charges.
Explanation:
The distance between the charges and the midpoint is d' =d/2
The electric field strength can be calculated by the formula

The electric field strength at the midpoint due to the charge q1 will be

The electric field strength at the midpoint due to the charge q2 will be

The electric field strength at the midpoint between the charges will be

The electric field strength at the midpoint between the two charges is 5.87 x 10^(5) m.
The velocity is changing.
Answer: 1.59 sec
Explanation:
The kinetic energy contained in the rotation of the cylinder is 1/2 m v^2
The kinetic energy of translation is also 1/2 m v^2
so the total energy is m v^2
The force applied is mg sin (theta)
= m x 9.8 x 1/2
= 4.9 m
Now equate
F x d = m v^2
4.9 m x 3.1 = m v^2
v^2 = 4.9 x 3.1
v = sqrt(4.9 x 3.1) = 3.9 m/s
Acceleration.
V^2 = 2 a s
4.9 x 3.1 = 2 x a x 3.1
4.9 = 2 a
a = 2.45 m/s^2
Time
T = v/a
= 3.9/2.45
= 1.59 sec