<span>
</span><span>Waves on a pond are an example of which kind of wave?
</span>B. surface waves
Answer:
the super train is not completely within the tunnel.
Explanation:
From the given information:
The proper length = 1200 ft
The super train speed = 0.99c
By applying the concept of length contraction, the contracted length of the super-train can be determined by using the formula:
L = 169.3 ft
≅ 169 ft
Thus, the contracted length is 169 ft more than the proper length of the tunnel L' 50 ft.
As such, the super train is not completely within the tunnel.
Assuming the driver starts slamming the brakes immediately, the car moves by uniformly decelerated motion, so we can use the following relationship
(1)
where
a is the deleceration
S is the distance covered after a time t
is the velocity at time t
is the initial speed of the car
The accident is 80 m ahead of the car, so the minimum deceleration required to avoid the accident is the value of a such that S=80 m and
(the car should stop exactly at S=80 m to avoid the accident). Using these data, we can solve the equation (1) to find a:
And the negative sign means it is a deceleration.