Ablock of mass 3m is released from rest at a height r above a horizontal surface. theacceleration due to gravity is g. the block slides along the inside of a frictionless circular hoop of radius r. what is the magnitude of the normal force exerted on the block by the hoop when the block has reached the bottom?

N = 3 mg

Explanation:

For this case we will use Newton's second law where acceleration is centripetal.

    F = m a

    a = v² / r

Let's write the expression for the lowest part of the hoop

    N- W = m a

    N = mg + m V2 / r

To find the speed let's use energy conservation

highest point

     Em₀ = U = m g y

lowest point

      = K = ½ m v²

    Em₀ =  

    mg y = ½ m v²

    v = √ 2gy

We substitute in the equation of the normal

    N = m (g 2g y/r )

Let's analyze the initial height it gives is that the body leaves a height R

    N = m (g + 2 g R / R)

     N = 3 mg

most voltage drop calculators want the distance between the source and destination. then internally, they double it so both the source and return wires are calculated. but you need to know which distance the calculator uses so you're not half of what you should be or double what you should be.

most circuit breakers will not take a #6 directly, so the electrician will have to splice on a smaller pigtail. you also have to upsize the grounding wire when you upsized the ungrounded (hot) wire (see note in 250.122). this will preclude using most cable assemblies, as a cable with #6 copper will most likely only have a #10 grounding conductor. you need a #6 grounding conductor if the circuit is 20a. a #8 cable is no better, as it will have a #10 grounding conductor too. but most 20a breakers will take a #8 directly.

in your related post, you didn't say what type of load this is. if it is a light or heater, voltage drop won't be a big issue. if this is a motor, the current needs are huge at startup and the voltage drop can pose a problem. if this is a motor, knowing if the motor is under much load during startup will answer the voltage drop effect (a saw is easier to start than a compressor).

f is prop to m1xm2 double m1 double force