Answer:
Friction can be increased the longer two objects are rubbed together, since the longer they are rubbed is the more heat produced.
Explanation:
Answer:
C) must be such as to follow the magnetic field lines.
Explanation:
Ampere's circuital law helps us to calculate magnetic field due to a current carrying conductor. Magnetic field due to a current forms closed loop around the current . If a net current of value I creates a magnetic field B around it , the line integral of magnetic field around a closed path becomes equal to μ₀ times the net current . It is Ampere's circuital law . There may be more than one current passing through the area enclosed by closed curve . In that case we will take net current by adding or subtracting them according to their direction.
It is expressed as follows
∫ B.dl = μ₀ I . Here integration is carried over closed path . It may not be circular in shape. The limit of this integration must follow magnetic field lines.
the term ∫ B.dl is called line integral of magnetic field.
The frequency of the wheel is given by:

where N is the number of revolutions and t is the time taken. By using N=100 and t=10 s, we find the frequency of the wheel:

And now we can find the angular speed of the wheel, which is related to the frequency by:
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Answer:

Explanation:
We have given that mass of electron 
It is given that initial velocity u=0 m/sec
Final velocity v = 
Distance S = 2.2 cm = 0.022 m
According to third law of motion 


Accelerating force F is given by F = ma
So accelerating force