He would try to enter as the tide is rising, and leave as the tide is falling. Those things happen at all different times of day during a month.
Molarity and molality both describe the concentration of a substance in terms of moles.
Molarity describes the number of moles of a substance per unit of volume, typically per liter (mol/l).
Molality describes the number of moles per unit of mass, typically kilograms (mol/kg).
When determining the molality of a solution, mol/kg can be obtained by finding the number of moles in the substance, and dividing that number by the the total weight in kilograms of that substance.
When determining the molarity of a solution, mol/l can be obtained by dividing the number of moles in a substance by the total volume in liters of that substance.
Answer:
The angular acceleration of the pencil<em> α = 17 rad·s⁻²</em>
Explanation:
Using Newton's second angular law or torque to find angular acceleration, we get the following expressions:
τ = I α (1)
W r = I α (2)
The weight is that the pencil has is,
sin 10 = r / (L/2)
r = L/2(sin(10))
The shape of the pencil can be approximated to be a cylinder that rotates on one end and therefore its moment of inertia will be:
I = 1/3 M L²
Thus,
mg(L / 2)sin(10) = (1/3 m L²)(α)
α(f) = 3/2(g) / Lsin(10)
α = 3/2(9.8) / 0.150sin(10)
<em> α = 17 rad·s⁻²</em>
Therefore, the angular acceleration of the pencil<em> </em>is<em> 17 rad·s⁻²</em>
Answer:
.
Explanation:
By Newton's Second Law, the acceleration 
of an object is proportional to the net force 
on it. In particular, if the mass of the object is 
, then
.
Rewrite this equation to obtain:
.
In this case, the assumption is that the 
force is the only force that is acting on the object. Hence, the net force on the object would also be
Make sure that all values are in their standard units. Forces should be in Newtons (same as 
, and the acceleration of the object should be in meters-per-second-squared (
). Apply the equation to find the mass of the object.
.
Answer:
F = 6.27 x 10 ¹⁹ N
Explanation:
Given
m₁ = 92 kg, m₂ = 46 kg, % = 0.04% N = 6.022 x 10²³ Z = 18, e = 1.6 x 10 ⁻¹⁹ C, M = 0.018 kg/mol
q₁ = % * [m * N * A * e / M ]
q₁ = 0.0004 * [ ( 92 kg * 6.022 x 10²³ * 18 * 1.6 x 10 ⁻¹⁹ ) / (0.018 kg/mol ) ]
q₁ = 3.54 x 10⁶ C
q₂ = 0.0004 * [ ( 46 kg * 6.022 x 10²³ * 18 * 1.6 x 10 ⁻¹⁹ ) / (0.018 kg/mol ) ]
q₂ = 1.773 x 10⁶ C
Now to determine the electrostatic force con use the equation
F = K * q₁ * q₂ / d²
K = 8.99 x 10 ⁹
F = 8.99 x 10 ⁹ * 3.54 x 10⁶ C * 1.773 x 10⁶ C / (30m)²
F = 6.27 x 10 ¹⁹ N
