1. What mass can be lifted by the hydraulic press if it is known that the are: of the small piston is 48cm and that of the large piston is 1440cm, and
the force acting on the small piston can be as large as 1000N. (use g =
10m/s)
C. 3000kg
B. 30kg
D. 30,000kg
A. 300kg

C. 3000kg

Explanation:

Hydraulic Jack

It's a device that is used to lift heavy loads by applying force via a hydraulic cylinder.

Since the internal pressure on the liquid of the jack is constant, the following relation applies:

Where

F1  = Force applied in one end of the jack

A1  = Area of the cylinder of the same end

F2  = Force applied in the other end of the jack

A2  = Area of the cylinder of the other end

If we assume the force is being applied on side 1, then the force on side 2 is calculated by solving for F2:

We have F1=1000N, A1= 48~cm^2, A2= 1440~cm^2, thus:

Since we need to know the mass that can be lifted by that force, we use the formula:

W = m.g

Where W is the weight of the mass and g= 10~m/s^2. Since the weight is equal to the force exerted by the jack:

m = 3000 Kg

C. 3000kg

b.

hope this : )

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.