Answer:
A) the pressure could crush the submarine
Explanation:
- The submarines are mainly used for defense purposes.
- In world war 1 and 2 the submarines played a vital role in the war.
- The submarines work according to the principle of buoyancy.
- According to this principle, when seawater is filled inside the tank in a required amount, the submarines sink.
- When the seawater is expelled, the submarine rises to above the sea.
- Most of the time, it dives deep into the sea, the hydrostatic pressure should be taken into account.
- If the hydrostatic pressure is not considered, the pressure could crush the submarine.
Answer:
The current can be controlled by modifying the resistance value
Explanation:
The current can be controlled by modifying the resistance value, usually a variable resistance device called potentiometer is used. This can be observed mathematically using the ohm law which is defined as voltage equal to the current product by resistance.
V = I*R
where:
I = current [amp]
R = resistance [ohm]
V = voltage [volt]
We can see that if we reduce the resistance the current will be increased
I = v / R
And if we amplify the resistance (R) the current will be diminished
Answer:
4) Driving in a straight line at 60 miles per hour
Explanation:
1) Driving 60 miles per hour around a curve
2) Going from 0 to 60 miles per hour in 10 seconds
3) Slamming on the brakes to come to a stop at a stop sign
4) Driving in a straight line at 60 miles per hour
1) The speed is constant here, but in circular motion you have an acceleration that is v^2/r, where v is the speed and r the radius
2) You are accelerating from 0 to 60
3) You are desaccelerating
4) constant speed , no acceleration
C. Magnetism
Very few minerals are magnetic, while streak hardness and specific gravity can be used to identify lots of minerals