Answer: a) speed = 3.45 × 10^-2 m/s
b) speed = 1.38 × 10^-1 m/s
Explanation: shown in the attachment
Answer:
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Answer:

Given:
Initial velocity (u) = 30 m/s
Final speed (v) = 0 m/s
Acceleration (a) = - 1.5 m/,s²
To Find:
Time in which train will come to rest (t).
Explanation:

So,
Time in which train will come to rest = 20 seconds
Answer:
The frequency is 302.05 Hz.
Explanation:
Given that,
Speed = 18.0 m/s
Suppose a train is traveling at 30.0 m/s relative to the ground in still air. The frequency of the note emitted by the train whistle is 262 Hz .
We need to calculate the frequency
Using formula of frequency

Where, f = frequency
v = speed of sound
= speed of passenger
= speed of source
Put the value into the formula


Hence, The frequency is 302.05 Hz.