Answer:
6.32m/s
Explanation:
note:Now these calculations are based in the fact that acc. due to gravity is 10m/s²
okay so I'm thinking you think the speed of a body depends on the mass of the body also,umh... well it doesn't at all!
when two bodies of different masses fall from the same height,they fall at the same time( this is just to say)
now enough of the talking let solve....
so the ball was dropped .ie from rest to the ground through a distance of 2m,
the formula for calculating the distance if a body moving in a straight line is given by:
S=ut + ½at² where u is initial velocity, a is acceleration ( of the body or due to gravity, but since its falling freely under the influence of gravity its " we use the acceleration due to gravity ,which is 10m/s²) and t is the time taken to cover the distance.
from our question the ball was dropped from rest thus its u is 0 therefore we use this equation to find the time it took to touch ground (S=½at²)
solving ....
we get t to be 0.632s
to find the speed we substitute t in the equation below:
V=u+at ,but since u=0
V=at =10•0.632=6.32m/s
therefore the speed the body uses to strike the ground is 6.32m/s
Answer:
B: False
Explanation:
The second law of thermodynamics states that: the entropy of an isolated system will never decrease because isolated systems always tend to evolve towards thermodynamic equilibrium which is a state with maximum entropy.
Thus, it means that the entropy change will always be positive.
Therefore, the given statement in the question is false.
Answer:
Explanation:
The power provided by a resistor (wire in this case) is given by:
.
The resistance of a wire is given by:
Where for the resistivity the one of the copper should be used: 
.
The area A is that of a circle, which written in terms of its diameter is:
Putting all together:
Which for our values is:
Empirical formula of compound is XF3
Compound consist of 65% F
In 100g of compound there is 65 g of F
= 65 / 19 moles of Fluorine = 3.421 moles
So moles of X = 3.421 / 3 = 1.140 moles
And in 100 g X
consist of 35 g
So the molar mass of X = 35 / 1.140 = 30.71 g = 31
approximately
And it is the mass of phosphorus
So the empirical formula for the compound is PX3
