Acylindrical can of radius 200mm has liquid weighs 50kg. find the height of liquid in cm in the can, if the density is 0.8g/cm3.

density = mass/volume

50 kg to g

50*1000 = 50,000 grams

200 mm to cm

200*0.1 = 20 cm

Substitute: 0.8=50,000/volume of a cylinder

volume of cylinder= (pi)(r^2)(h)

volume of cylinder=(pi)(20^2)(h)

0.8=50,000/((pi)(20^2)(h))

0.8=50,000/400*pi*h

50,000/0.8=400*pi*h

62,500=400*pi*h

62,500/(400*pi)=h

h≈49.74 cm

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.

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)