Ametal block of mass 265 g rests at a point 2.4 m from the center of a horizontal rotating wooden platform. the coefficient of static friction between the block and the platform is 0.257. the platform initially rotates very slowly but the rotation rate is gradually increasing. the acceleration of gravity is 9.8 m/s 2 . at what minimum angular velocity of the platform would the block slide away? answer in units of rad/s.

The minimum angular velocity of the platform what whould the block slides away is w= 2.26 rad/s.

Explanation:

m= 0.265 kg

r= 2.4 m

μ= 0.257

g= 9.8 m/s²

W= m * g

W= 2.597 N

Fr= μ * W

Fr= 0.66 N

∑F = m * ac

W+Fr = m * ac

(W+ Fr) / m = ac

ac= 12.29 m/s²

ac= w² * r

√(ac/r)= w

w= 2.26 rad/s

firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.

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.