Answer:
D. "The net force is zero, so the acceleration is zero"
Explanation:
edge 2020
A. Impulse is simply the product of Force and time.
Therefore,
I = F * t --->
1
where I is impulse, F is force, t is time
However another formula for solving impulse is:
I = m vf – m vi --->
2
where m is mass, vf is final velocity and vi is initial
velocity
Therefore using equation 2 to solve for impulse I:
I = 2000kg (0) – 2000kg (77 m/s)
I = -154,000 kg m/s
B. By conservation of momentum, we also know that Impulse
is conserved. That means that increasing the time by a factor of 3 would still
result in an impuse of -154,000 kg m/s. So,
I = F’ * (3 t) = -154,000 kg m/s
Since t is multiplied by 3, therefore this only means
that Force is decreased by a factor of 3 to keep the impulse constant,
therefore:
(F/3) (3t) = -154,000 kg m/s
Summary of Answers:
A. I = -154,000 kg m/s
B. Force is decreased by factor of 3
The locks referred to here are the elevators that are used to transport boats safely from one water level to another in dams. These two varying water depths allow river traffic to operate The attached picture shows how boats enter locks in dam sites.
To regulate traffic, there are traffic lights that signal boatmen to adjust their speed when approaching the lock. The red light means to stop and to steer clear away from the lock to allows the boats inside to exit. The green light signals to enter the lock. Lastly, the amber light means approach the lock at a safe speed and under full control.