A 32-cm-long solenoid, 1.8 cm in diameter, is to produce a 0.30-T magnetic field at its center. If the maximum current is 4.5 A,
1 answer:
Answer:
<h2>16,931 turns</h2>Explanation:
The magnetic field produced is expressed using the formula
B is the magnetic field = 0.30T
I is the current produced in the coil = 4.5A
is the magnetic permittivity in vacuum = 1.26*10^-6Tm/A
L is the length of the solenoid = 32 cm = 0.32 m
N is the number of turns in the solenoid.
Making N the subject of the formula from the equation above;
Substituting the give values to get N;
The number of turns the solenoid must have is approximately 16,931 turns
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Answer:
v= 4.0 m/s
Explanation:
- When standing on the bathroom scale within the moving elevator, there are two forces acting on Henry's mass: Normal force and gravity.
- Gravity is always downward, and normal force is perpendicular to the surface on which the mass is located (the bathroom scale), in upward direction.
- Normal force, can adopt any value needed to match the acceleration of the mass, according to Newton's 2nd Law.
- Gravity (which we call weight near the Earth's surface) can be calculated as follows:
- According to Newton's 2nd Law, it must be met the following condition:
- As the gravity is larger than normal force, this means that the acceleration is downward, so, we choose this direction as the positive.
- Solving for a, we get:
- We can find the speed after the first 3.8 s (assuming a is constant), applying the definition of acceleration as the rate of change of velocity:
- Now, if during the next 3.8 s, normal force is 930 N (same as the weight), this means that both forces are equal each other, so net force is 0.
- According to Newton's 2nd Law, if net force is 0, the object is either or at rest, or moving at a constant speed.
- As the elevator was moving, the only choice is that it is moving at a constant speed, the same that it had when the scale was read for the first time, i.e., 4 m/s downward.