Answer:
a)W= - 720 J
b)ΔU= 330 J
Explanation:
Given that
P = 0.8 atm
We know that 1 atm = 100 KPa
P = 80 KPa
V₁ = 12 L = 0.012 m³ ( 1000 L = 1 m³)
V₂ = 3 L = 0.003 m³
Q= - 390 J ( heat is leaving from the system )
We know that work done by gas given as
W = P (V₂ -V₁ )
W= 80 x ( 0.003 - 0.012 ) KJ
W= - 0.72 KJ
W= - 720 J ( Negative sign indicates work done on the gas)
From first law of thermodynamics
Q = W + ΔU
ΔU=Change in the internal energy
Now by putting the values
- 390 = - 720 + ΔU
ΔU= 720 - 390 J
ΔU= 330 J
The magnitudes of his q and ∆H for the copper trial would be lower than the aluminum trial.
The given parameters;
- <em>initial temperature of metals, = </em>
<em /> - <em>initial temperature of water, = </em>
<em> </em> - <em>specific heat capacity of copper, </em>
<em> = 0.385 J/g.K</em> - <em>specific heat capacity of aluminum, </em>
= 0.9 J/g.K - <em>both metals have equal mass = m</em>
The quantity of heat transferred by each metal is calculated as follows;
Q = mcΔt
<em>For</em><em> copper metal</em><em>, the quantity of heat transferred is calculated as</em>;

<em>The </em><em>change</em><em> in </em><em>heat </em><em>energy for </em><em>copper metal</em>;

<em>For </em><em>aluminum metal</em><em>, the quantity of heat transferred is calculated as</em>;

<em>The </em><em>change</em><em> in </em><em>heat </em><em>energy for </em><em>aluminum metal </em><em>;</em>

Thus, we can conclude that the magnitudes of his q and ∆H for the copper trial would be lower than the aluminum trial.
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Answer:
She must be launched with minimum speed of <u>57.67 m/s</u> to clear the 520 m gap.
Step-by-step explanation:
Given:
The angle of projection of the projectile is,
°
Range of the projectile is,
m.
Acceleration due to gravity, 
The minimum speed to cross the gap is the initial speed of the projectile and can be determined using the formula for range of projectile.
The range of projectile is given as:

Plug in all the given values and solve for minimum speed,
.

Therefore, she must be launched with minimum speed of 57.67 m/s to clear the 520 m gap.
Kinetic energy = 1/2 m v²
If we reduce the mass by half > m/2
Kinetic energy = 1/2 m/2 v²
We should know that 1/2 × 1/2 = 1/4
So kinetic energy will be :
1/4 × m × v²
Answer:
Q = 1.35*10⁻¹¹ C.
Explanation:
By definition, the capacitance of a capacitor, is the charge on one of the plates, divided by the potential difference between them, as follows:

At the same time, we can show (applying Gauss' Law to the surface of one of the plates), that the capacitance of a parallel-plate capacitor (with a dielectric of air), can be written as follows:
C = ε₀*A / d
Replacing by the values of A, and d, and taking into account that
ε₀ = 8.85*10⁻¹² F/m,
we get the value of the capacitance as follows:
C = 8.97*10⁻¹² F
As the voltage of an AA battery is 1.5 V, and is all applied to the capacitor, we can conclude that the charge on one of the plates is as follows:
Q = C* V = 8.97*10⁻¹² F* 1.5 V = 1.35*10⁻¹¹ C