This is another one of those muddy misleading questions, followed by
a muddy group of choices from which an answer must be selected.
a). is absurd. There's no such thing as a "balanced force", only
a balanced group of forces.
b). is probably the choice the question is aiming for.
c). is not so. The engines of an airplane do plenty of work lifting the plane
off the ground, although the force of the engines is never directed upward.
d). is really awkward. The object's motion is almost never the cause of the force.
The force is almost always the cause of the object's motion.
Now for the big 800-lb gorilla in the room: No moving object needs to be involved
in order for energy to be flowing or work to be getting done.
-- A radio wave radiates through space. Straighten out a wire coat-hanger and
stick it up in the air where the radio wave can pass by it. Electrical current flows
through the wire, and you can drain the electrical energy out the bottom of it.
-- A light bulb is shining. Some distance away, something it's shining on
gets warm, because of the heat energy that has shot across to it from the
light bulb and soaked into it.
-- A lightning bolt jumps from the ground to a passing cloud. Or, if you feel
more comfortable with it, a lightning bolt jumps from a cloud to the ground.
It doesn't matter. Either way, there's enough energy splashing around to
ignite houses, zap TVs and computers, melt concrete, vaporize water, and
light up a city. Although nothing is moving.
Answer:A solenoid is a simple electromagnetic device consisting of a coiled electric wire, wrapped in a 3D circular pattern. When electric current is passed through the wire, the solenoid acts like a magnet with N and S poles at the ends of the coil.
When a ferromagnetic material rod is permanently placed inside the solenoid, the metal greatly increases the magnetic effect and becomes a permanent electromagnet. Moreover, it can also be used as an electrical switch by drawing in or pushing out a ferromagnetic material like an iron rod. Depending on the directions of the rod and the electrical current the switching action takes place.
Given figure represents the solenoid as electromagnet and the switching action.
Explanation:
Given:
Circumference = 2 m
Angular speed, ω = 1 rev/s = 2π radians/s
If the radius is r, then
2πr = 2
r = 1/π m
The linear (tangential) speed is
v = rω
= (1/π m)*(2π rad/s) = 0.5 m/s
Answer: 0.5 m/s
An arrow pointing from the bottom of the ramp to the top, I assume it would be friction.
