The answer is 96 ..................................................
Answer:
The concentration of mole evil at oxygen on that day is 0.00858 mol/L
Explanation:
Here, we want to calculate the concentration of molecular oxygen
The pressure on that day is 1.0 atm
Since oxygen is at a concentration of 21%, the pressure of oxygen will be 21/100 * 1 = 0.21 atm
Now let’s calculate the concentration;
From Ideal gas law;
PV = nRT
This can be written as;
P/RT = n/V
The term n/V refers to concentration;
Let’s make substitutions now;
P = pressure = 0.21 atm
R = molar gas constant = 0.0821 L•atm/mol•k
T = temperature = 25 = 25 + 273.15 = 298.15 K
Substituting these values, we have;
n/V = C = 0.21/(0.0821 * 298.15) = 0.00858 mol/L
Answer:
(a) 5.7 s
(b) 39 m/s
Explanation:
(a) u = 18 m/s
At the maximum height, the final velocity of ball is zero. lte teh time taken by the ball to go from 50 m height to maximum height is t.
use first equation of motion.
v = u + g t
0 = 18 - 10 x t
t = 1.8 s
Let the maximum height attained by the ball when it thrown from 50 m height is h'.
Use third equation of motion
v^2 = u^2 + 2 g h'
0 = 18^2 - 2 x 10 x h'
h' = 16.2 m
Total height from the ground H = h + h' = 50 + 16.2 = 76.2 m
Let t' be the time taken by the ball to hit the ground as it falls from maximum height.
use third equation of motion
H = ut + 1/2 x g t'^2
76.2 = 0 + 1/2 x 10 x t'^2
t' = 3.9 s
Total time taken by the ball to hit the ground = T = t + t' = 1.8 + 3.9 = 5.7 s
(b) Let v be the velocity with which the ball strikes the ground.
v^2 = u^2 + 2 g H
v^2 = 0 + 2 x 10 x 76.2
v = 39 m/s
I believe a but none sound like they’d build a laser
Answer:
19320 kg/m³
Explanation:
density: This can be defined as the ratio of the mass of a body to its volume. The S.I unit of Density is kg/m³.
The formula of density is given as,
D = m/v ......................... Equation 1.
Where D = Density of the gold, m = mass of the gold, v = volume of the gold.
Note: From Archimedes's Principle, the piece of gold displace an amount of water that is equal to it's volume.
Amount of water displace = 27.2 - 25 = 2.2 mL.
Given: m = 42.504 g = 0.042504 kg, v = 2.2 mL = (2.2/10⁶) m³ = 0.0000022 m³
Substitute into equation 1
D = 0.042504/0.0000022
D = 19320 kg/m³
Hence the density of the piece of gold = 19320 kg/m³