Flywheels are large, massive wheels used to store energy. they can be spun up slowly, then the wheel's energy can be released quickly to accomplish a task that demands high power. an industrial flywheel has a 1.5 m diameter and a mass of 250 kg. its maximum angular velocity is 12000 rpm. a motor spins up the flywheel with a constant torque of 50 nm. how long does it take the flywheel to reach top speed?

t = 1767.43 s

Explanation:

given,

diameter of fly wheel = 1.5 m

mass = 250 Kg

angular speed = 12000 rpm

                        = 12000 x 2π/60

                        = 1256.64 rad/s

torque = 50 Nm

moment of inertia of disk

        I = 70.3125 Kg.m²

we know,

    τ = I α

           α = 0.711 rad/s²

using equation of rotational motion

   ω = ω₀ + α t

    1256.64 = 0 + 0.711 x t

        t = 1767.43 s

f is prop to m1xm2 double m1 double force

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.