1. compare these objects:
object alpha is a hoop of mass 55kg and radius .24m;
object bravo is a disk of mass 86kg and radius .24m;
object charlie is a sphere of mass 112kg and radius .24m.
a) calculate the rotational inertias of each object?

|hoop |disk |sphere
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b) which object would win a race down an inclined plane?

I = 3.168

I = 2.48

I = 2.58

Charlie

Object Alpha is a hoop of mass 55kg and radius 0.24m

Formula to use

I = (m)(r)(r)

I = 55(0.24)²

I = 3.168

Object Bravo is a disk of mass 86kg and radius .24m

Formula to use

I = 1/2(m)(r)(r)

I = 1/2(86)(0.24)²

I = 2.48

Object Charlie is a sphere of mass 112kg and radius .24m

Formula to use

I = 2/5(m)(r)(r)

I = 2/5(112)(0.24)²

I = 2.58

As solid(sphere) object will always roll down the ramp faster than a hollow(disk, hoop) object of the same shape so Charlie will win the race down the incline plane

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.

continuous conducting path for current, power supply