Answer:
B 1500N
Explanation:
The acceleration of the car - at least the average one, but that will do, is 
We know the acceleration, we know the force, let's drop them in Newton second law.

1.Synovial joint
2. pivot joint
3. Hinge joint
Answer:
-3 m/s²
Explanation:
The formula for deceleration is given as the change in speed over a period of time
Given that,
Initial speed = 15 m/s
Final speed = 3 m/s
change in speed= 3-15= -12 m/s
Time taken= 4 sec
Deceleration = -12/4 = -3 m/s²
Answer
a = 3.674 m / s ^ 2
t = 3.13 s
Using the kinematic equations for the movement we have:
(1)
(2)
Where:
= initial position
= initial velocity
a = acceleration
t = time in seconds
= final speed
We know:


h = 18 m

So:
From (2) we have that: 

From (1) we have to:

Then we clear "a" to find the acceleration.

Then, the time it takes to reach this speed is:

the second level will have 8 electrons.