<span>Pitch and frequency are more or less the same thing - high pitch = high frequency.
The freqency of vibration of a string f = 1/length (L) so as length decreases the frequency increases.</span>
Answer: The trip takes 
Explanation:
Velocity
is the variation of the position of a body (distance traveled
) with time
:
In this case, the car travels a distance
at a velocity
and we need to find the time it takes the trip.
Isolating
:

Finally:

Answer:
a) 17.49 seconds
b) 13.12 seconds
c) 2.99 m/s²
Explanation:
a) Acceleration = a = 1.35 m/s²
Final velocity = v = 85 km/h = 
Initial velocity = u = 0
Equation of motion

Time taken to accelerate to top speed is 17.49 seconds.
b) Acceleration = a = -1.8 m/s²
Initial velocity = u = 23.61\ m/s
Final velocity = v = 0

Time taken to stop the train from top speed is 13.12 seconds
c) Initial velocity = u = 23.61 m/s
Time taken = t = 7.9 s
Final velocity = v = 0

Emergency acceleration is 2.99 m/s² (magnitude)
The statement to every reacting there is, there is a opposite and same reacting.
hope it helps