Answer:
7.5 kg
Explanation:
We are given that
Length of plank, l=3 m
Distance of fulcrum from one end of the plank=1 m
We have to find the mass must be on the other end if the plank remains balanced.
Let m be the mass must be on the other end if the plank remains balanced.
In balance condition
Hence, mass 7.5 kg must be on the other end if the plank remains balanced.
Hydrogen (H) has a molar mass of about 1.007 g/mol and has 1 electron.
Oxygen (O) has a molar mass of about 15.999 g/mol and has 8 electrons.
Then water (H₂O) has a total molar mass of about 18.015 g/mol and has 10 electrons.
30 g of water is the mass of
(30 g) × (1/18.015 mol/g) ≈ 1.66528 mol
of water. Recall that 1 mole is around 6.022 × 10²³ molecules (i.e. Avogadro's number). So 30 g of water is the mass of approximately 1.00285 × 10²⁴ molecules of water.
If each molecule contains 10 electrons, then 30 g of water contains 1.00285 × 10²⁵ ≈ 10²⁵ electrons.
Velocity is distance/time
so 150/7200=.0208km/s
unless you have to convert it to miles or something else. but use the formula!
By definition, acceleration is the change in velocity per change of time. As time passes by, the time increases in value. So, when the acceleration is decreasing while the time is increasing, then that means that the change of velocity is also decreasing with time. So, optimally, the initial velocity and the velocity at any time are very relatively close to each other,
