Two blocks, stacked one on top of the other, slide on a frictionless horizontal surface. The surface between the two blocks is rough, however, with a coefficient of static friction equal to 0.40. The top block has a mass of 2.9 kg, and the bottom block's mass is 5.8 kg. If a horizontal force F is applied to the bottom block, what is the maximum value F can have before the top block begins to slip?

The value is

Explanation:

From the question we are told that

    The coefficient of static friction is  

    The mass of the top of block  is  

     The mass of the  bottom is  

Generally given that the frictional force between the bottom block and the frictionless horizontal is zero then the maximum value F can have before the top block begins to slip will be equal to the frictional force between the top and  the bottom block which is mathematically represented as

Here N is the normal force acting on top block which is mathematically represented as

=>

So

=>  

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.

a sonic boom is a loud boom that breaks the sound barrier

explanation: