Answer:
1.013 s
Explanation:
You can solve this problem using the equations for constant acceleration motion. The velocity at the bottom of the window can be found using this expression:

the gravity is negative as it opposes the movement.

Now, the time elapsed before the ball reappears is 2 times the time that it takes for the ball to go from the bottom of the window, reach maximum height, and reach again the bottom of the window, minus 2 times the time that it takes for the ball to travel from the top to the bottom of the window. The time that takes to the ball to reach maximum height, or in other words, to time that takes for the velocity of the ball to go from vo to 0m/s:

Then:

Answer is D - from the equation of electric field for point charge
Answer:
The frictional force acting on the bear during the slide is 207.5 N
Explanation:
Given;
mass of beam, m = 25-kg
vertical height, h = 12 m
speed of fall, v = 6 m/s
Change in potential energy of the beam:
ΔP.E = -mgh = - 25 x 9.8 x 12 = -2940 J
Change in kinetic energy of the beam:
Δ K.E = ¹/₂mv² = ¹/₂ x 25 x (6)² = 450 J
Change in thermal energy of the system due to friction:
ΔE = - (ΔP.E + Δ K.E)
ΔE = - (-2940 J + 450 J)
ΔE = 2940 J - 450 J = 2490 J
Frictional force (in N) acting on the bear during the slide:
F x d = Fk x h = ΔE
Where;
Fk is the frictional force
Fk = ΔE/h
Fk = 2490J / 12m
Fk = 207.5 N
Therefore, the frictional force acting on the bear during the slide is 207.5 N
The area of the plates must have is(A)= 9.91×10⁷ m²
<h3 /><h3>How can we calculate the value of a area of a capacitor?</h3>
To calculate the the value of a area of the plates of a capacitor, we are using the formula,
C=
Or, A= 
Here we are given,
C= The desired capacitance of a capacitor.
= 0.23F
d=distance of separation between the plates.
=3.8mm= 0.0038m.
= permittivity of the vacuum.
=8.854×10⁻¹²F/m
We have to calculate the area of the plates must have = A m².
Now we put the known values in the above equation, we can get
A= 
Or, A=
Or, A= 9.91×10⁷ m²
From the above calculation, we can conclude that the area of the plates must have is(A)= 9.91×10⁷m²
Learn more about Capacitor:
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Answer:
Explanation:
Constant pressure molar heat capacity Cp = 29.125 J /K.mol
If Cv be constant volume molar heat capacity
Cp - Cv = R
Cv = Cp - R
= 29.125 - 8.314 J
= 20.811 J
change in internal energy = n x Cv x Δ T
n is number of moles , Cv is molar heat capacity at constant volume , Δ T is change in temperature
Putting the values
= 20 x 20.811 x 15
= 6243.3 J.