Which body is in equilibrium?
(1) a satellite orbiting Earth in a circular orbit
. No. The forces on it are unbalanced. There's only one force acting on it ... the force of gravity, pulling it toward the center of the Earth. That's a centripetal force, and the satellite is experiencing centripetal acceleration.
(2) a ball falling freely toward the surface of Earth. No. The forces on it are unbalanced. There's only one force acting on it ... the force of gravity, pulling it toward the center of the Earth. The ball is accelerating toward the ground.
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(3) a car moving with a constant speed along a straight, level road. YES.</em> We don't even need to analyze the forces, just look at the car. It's moving in a straight line, and its speed is not changing. The car's acceleration is zero ! That right there tells us that the NET force ... the sum of all forces acting on the car ... is zero. THAT's called 'equilibrium'.
(4) a projectile at the highest point in its trajectory. No. The forces on it are unbalanced. There's only one force acting on it ... the force of gravity, pulling it toward the center of the Earth. The projectile is accelerating toward the ground.
First question:
The magnitude of current flowing in a circuit is described in
units of Amperes. The device used to measure it is an Ampmeter,
or Ammeter.
Second question:
This question is so absurd that it should not be dignified with an
answer. Although 'E' is often used as the symbol for Electromotive
force, potential difference, and voltage, there's certainly no rule.
Anyone is free to use 'M', 'Q', 'Θ', or 'Щ' to denote voltage when
they write electrical formulas, just as long as they make sure to
explain the meaning of whatever symbols they use.
Not sure, nobody knows hopefully soon we will know
Answer: A medium is any substance or region through which a wave is transmitted. The speed of a wave is dependant on four factors: wavelength, frequency, medium, and temperature. Wave speed is calculated by multiplying the wavelength times the frequency (speed = l * f).
