Two blocks with rough surfaces are stacked on top of a slippery horizontal surface. The top block has a mass of m, and the bottom block a mass of 2m. A rope of negligible mass is attached to the bottom block and the other end is hung over a pulley with negligible friction and mass, where it is attached to a hanging block of mass 3m. The friction force between the two blocks keeps the top block from sliding off the bottom block, and the hanging block is released as the system begins at rest. Find the contact forces, the friction force, the tension force, and the distance the hanging weight drops in a time t. Your answers should all be in terms of m, g, and t.

Contact and tension force: 3mg

Friction force: mg

Distance the hanging block would drop in a time t:

Explanation:

The gravity force on the hanging block would be:

Which is the contact force that directly affect the 2 stacked-block system, which would have an acceleration of:

So the friction force that pulls the top block must be

Since the pulley has negligible mass and radius, the tension force would be the same as contact force, which is 3mg

Now that the system moves with an acceleration of g, then after t (seconds), the hanging block would have dropped by a distance of

"i have always loved contemporary art and made it a general goal to work within the field. after a few nonprofit internships at museums and galleries, i decided to try the for-profit art world and was offered a job as the ad assistant at the magazine. i much prefer the pace of the for-profit art community and have stayed with the company for three years, with a promotion to an account manager last spring."

i just did this and got a 100.

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.