Explanation:
a straight line under the letter

<h2>Speed = Distance/Time</h2>
If a train travelled 500 meters in 25 seconds then,
Speed = 500m/25sec
<h2>
→ 20 m/sec</h2>

Answer:
The diameter of the needle is <u>4.675 cm</u>.
Explanation:
Given:
Volume flow rate is, 
Velocity of air expelled by pump is, 
Let the area of the needle be 'A' cm² and the diameter be 'd' cm.
We know that, volume flow rate of the air expelled by pump is given as the product of the needle's area and velocity of air flowing through that area.
Therefore, volume flow rate is given as:

Now, considering the needle to be circular, area of the needle can be written as:

Therefore, the diameter of the needle is 4.675 cm.
Answer:
The maximum speed is 21.39 m/s.
Explanation:
Given;
radius of the flat curve, r₁ = 150 m
maximum speed,
= 32.5 m/s
The maximum acceleration on the unbanked curve is calculated as;

the radius of the second flat curve, r₂ = 65.0 m
the maximum speed this unbanked curve should be rated is calculated as;

Therefore, the maximum speed is 21.39 m/s.