Rezolvati urmatoarele probleme, urgent, dau coroana 1. În 400 grame soluţie se găsesc 80 grame zahăr. Ce concentraţie procentuală are soluţia?
2. În 500 Kg soluţie sunt dizolvate 75 Kg sodă de rufe. Ce concentraţie procentuală are soluţia ?
3. Ce cantitate de soluţie de concentraţie 15% se obţine prin dizolvarea a 60 Kg piatră vânătă în apă ?

first let us lay out the formula for potential

and kinetic energy:

pe = mgh

ke = (mv^2)/2

where: m=mass, v=velocity, g=gravitational

acceleration, h=height

calculating for mass using the known values of

pe:

340j = m (9.81 m/s^2) (50ft) (1m/3.28ft)

m = 2.27 kg

the law of conservation of energy states that

energy is neither created nor destroyed. therefore, the change in kinetic

energy from 50 ft to 35 ft would be equal to the change in potential energy

from 50 ft to 35 ft. however it would be opposite in signs since one is losing

while other is gaining.

ke(35ft) – ke(50ft) = - [ pe(35ft) – pe(50ft]

ke(50ft) = 0 since the brick is initially at rest

ke(35ft) = 340j - 2.27kg (9.81 m/s^2) (35ft)

(1m/3.28 ft)

ke(35ft)

= 102.38 j

aquifers are bounded above and below by impermeable rock. the driving force of groundwater movement in confined aquifers is pressure, rather than gravity.