The final velocity is half of train car B's initial velocity.

**Answer:**

**90m/s**

**Explanation:**

Given parameters:

Acceleration = 10m/s²

Time of fall = 9s

Unknown:

Final velocity = ?

Solution:

We can assume that the cart falls from rest.

Initial velocity = 0m/s

Using

v = u + gt

v is the final velocity

u is the initial velocity

g is the acceleration due to gravity

t is the time

v = 0 + 10 x 9 = **90m/s**

According to the <span> Newton's second law of motion</span>:

**Force = mass × acceleration**

Acceleration = change in speed ÷ time

Therefore,

Force =mass × (change in speed/time)

Acceleration = 40 m/s ÷ 1.1 millisecond

Acceleration = 40 m/s ÷ 0.001 seconds

**Acceleration = 40,000 m/s²**

Hence,

**F = m × a**

F = 0.155 kg × 40,000 m/s²

**F = 4,600 kg·m/s² (Newtons)**

**Answer:**

a. E=6.5*10^{5}N/C

b. E=-4.7*10^{4}N/C

**Explanation:**

We can use the result of applying the Gauss theorem to a infinite line of charge

with r the perpendicular distance to the line of charge. The total field will be the sum of the contribution to the field by each line of charge.

E=E1+E2

we have

+8.00 μC/m

-6.00 μC/m

y=1m

**(a)** ** y2=0.2m**

**(b) y3=0.616m**

In this case the field is directed toward the line of charge placed in y=1m

I think the answer is Ten. Hope i helped

just asking do you do K-12