Hi there,
Unlike velocity,speed is scalar,which means it is described by MAGNITUDE only.
Answer:
= 2.471 yards/s
Explanation:
We can calculate the average velocity thus:

Where
: First 25 yards
: Time to travel 
: Seconds 25 yards
: Time to travel 
Thus

= 2.471 yards/s
A DC voltmeter may be used directly to measure B. Polarity
Answer: 1 = Heat
2=gas
3=it gets hot enough to boil because the metal conducts the heat into the water to heat it up and eventually boil.
Explanation: its common sense