Answer:
a) The speed is 61.42 m/s
b) The drag force is 10.32 N
Explanation:
a) The Reynold´s number for the model and prototype is:


Equaling both Reynold's number:

Clearing Vm:

b) The drag force is:

Answer:
E = 420.9 N/C
Explanation:
According to the given condition:

where,
E = Magnitude of Electric Field = ?
v = speed of charge = 230 m/s
B = Magnitude of Magnetic Field = 0.61 T
θ = Angle between speed and magnetic field = 90°
Therefore,

<u>E = 420.9 N/C</u>
Answer:
<em>The difference in pressure between the external air pressure, and the internal air pressure of the middle ear.</em>
Explanation:
First of all, we should note that pressure decreases with height and increases with depth. The air within the middle ear (between the ear drum and the Eustachian tube) adjusts itself to respond to the atmospheric pressure, or when we yawn. At a high altitude like on the hill, the air pressure in the middle ear, is fairly low (this is to balance the low air pressure at this height). While riding down the hill quickly, there is little time for the air pressure in the ear to readjust itself to the increasing external air pressure, causing the external air to push into the ear drum. Along the way, the air within the middle ear is adjusted by the opening of the Eustachian tube, allowing more air into the space in the middle ear to balance the external air pressure. This readjustment causes the ear to pop.
Answer:
Increasing length increases resistance
increasing cross sectional area reduces the resistance
.
Explanation:
The formula for resistance of an object is

where r is resistance, d is resistivity of the material, l is length of material and a is cross sectional area of the object. This equation shows us that resistance is directly proportional to length and inversely proportional to cross sectional area. Hence, increasing length increases resistance while increasing cross sectional area reduces the resistance.
If these 2 variables are varied to the same extent, the net effect can be zero on the resistance.