As a bacterium swims through water it propels itself with its flagella so as to overcome the frictional drag forces and move at, more or less, constant velocity of 100 micrometer/s for periods of time. If the frictional drag force on a bacterium is 0.1 N, how much work does the bacterium do in 1 s?

A) 1 milliJoule

B) 10 microJoule

C) 100 microJoule

D) 1 J

E) 100 milliJoule

B) 10 microJoule

Explanation:

Given

v = 100 micrometer/s

F = 0.1 N

t = 1 s

we get the displacement as follows

d = v*t  ⇒  d = (100 micrometer/s)*(1 s) = 100 micrometer

then we apply the formula

W = F*d*Cos ∅

⇒  W = (0.1 N)*(100 micrometer)*Cos 0°

⇒  W = 10 microJoule

the arctic is a region of the planet, north of the arctic circle, and includes the arctic ocean, greenland, baffin island, other smaller northern islands, and the far northern parts of europe, russia (siberia), alaska and canada.

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation: