Answer:
The magnetic field in the center of the solenoid is 
.
Explanation:
Given that,
Length of solenoid = 0.425 m
Number of turns N = 950
Current I = 2.75 A
The magnetic field in the center of the solenoid is the product of the current , number of turns per unit length and permeability.
In mathematical form,
Where, 
N = number of turns
L = length
I = current
Now, The magnetic field
Put the value into the formula
Hence, The magnetic field in the center of the solenoid is .
Answer: 71.7 KJ
Explanation:
The rotational kinetic energy of a rotating body can be written as follows:
Krot = ½ I ω2
Now, any point on the rim of the flywheel, is acted by a centripetal force, according to Newton’s 2nd Law, as follows:
Fc = m. ac
It can be showed that the centripetal acceleration, is related with the angular velocity and the radius, as follows:
ac = ω2 r
We know that this acceleration has a limit value, so , we can take this limit to obtain a maximum value for the angular velocity also.
As the flywheel is a solid disk, the rotational inertia I is just ½ m r2.
Replacing in the expression for the Krot, we have:
Krot= ½ (1/2 mr2.ac/r) = ¼ mr ac = ¼ 67.0 Kg. 1.22 m . 3,510 m/s2 = 71. 7 KJ
Answer:
Option D
Explanation:
The work done can be given by the mechanical energy used to do work, i.e., Kinetic energy and potential energy provided to do the work.
In all the cases, except option D, the energy provided to do the useful work is not zero and hence work done is not zero.
In option D, the box is being pulled with constant velocity, making the acceleration zero and thus Kinetic energy of the system is zero. Hence work done in this case is zero.
They both are two different elements.SO the answer is Element
B: Energy lose
i say this because in order to change they lose energy.
