<span>The weight lifted by a machine to the applied force on a machine is called mechanical advantage.
This is written as Mechanical advantage, M. A, = load(weight)/effort.
So for 1) M.A = 2 and load = 2, 000lb = 8896.446N.
So 2 = 8896.446/ effort
Effort = 8896.446/2 = 4448.48
Similarly for M.A of 2, 000, 000 we have
Effort = 8896.446/ 2, 000, 000 = 0.004448</span>
Answer:
<em>the minimum speed that the ball must have so that the cord does not become slack is</em> <em>2.02 m/s.</em>
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Explanation:
In order to avoid slack, the centripetal force of the ball must equal its weight at the top of the circle. Therefore,
F_c = F_g
m v² / r = m g
v² = g r
v = √[g r]
v = √[(9.8 m/s²)(0.417 m)]
<em>v = 2.02 m/s </em>
Therefore,<em> the minimum speed that the ball must have so that the cord does not become slack is</em> <em>2.02 m/s.</em>
Answer:
D. is always perpendicular to the surface of the conductor
Explanation:
1) Answer is (D) option. Electric field just outside surface of charged conductor is normal to conductor at that point.
It can be explained on the basis of the fact that, Electric field inside conductor under static condition is zero. As a result potential difference between any two points with in conductor is zero. So whole of conductor is equipotential body.
Equipotential surface and Electric field lines always cut at 90 degrees to each other. Conductor being equipotential body, Electric field lines starting or terminating at conductor must be normal to surface. Hence electric field just outside conductor is perpendicular or normal to surface.
Explanation:
For this problem we have to take into account the expression
J = I/area = I/(π*r^(2))
By taking I we have
I = π*r^(2)*J
(a)
For Ja = J0r/R the current is not constant in the wire. Hence

and on the surface the current is

(b)
For Jb = J0(1 - r/R)

and on the surface

(c)
Ja maximizes the current density near the wire's surface
Additional point
The total current in the wire is obtained by integrating

and in a simmilar way for Jb
![I_{T}=\pi J_{0} \int\limits^R_0 {r^{2}(1-r/R)} \, dr = \pi J_{0}[\frac{R^{3}}{3}-\frac{R^{2}}{2R}]=\pi J_{0}[\frac{R^{3}}{3}-\frac{R^{2}}{2}]](https://tex.z-dn.net/?f=I_%7BT%7D%3D%5Cpi%20J_%7B0%7D%20%5Cint%5Climits%5ER_0%20%7Br%5E%7B2%7D%281-r%2FR%29%7D%20%5C%2C%20dr%20%3D%20%5Cpi%20%20%20J_%7B0%7D%5B%5Cfrac%7BR%5E%7B3%7D%7D%7B3%7D-%5Cfrac%7BR%5E%7B2%7D%7D%7B2R%7D%5D%3D%5Cpi%20J_%7B0%7D%5B%5Cfrac%7BR%5E%7B3%7D%7D%7B3%7D-%5Cfrac%7BR%5E%7B2%7D%7D%7B2%7D%5D)
And it is only necessary to replace J0 and R.
I hope this is useful for you
regards