An object has an acceleration of 12.0 m/s/s. The mass of the object is doubled while the net force on the object is held constan
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Answer:15,883.63 KJ
Explanation:
Given
Power=400 W
Freezing compartment temperature is 273 K
Outside air Temperature=306 K
Time =80 minutes
Energy Required to deliver 400 w power in 80 minutes
E=1920 KJ
and we know COP of refrigerator is given by
Therefore 15,883.63 KJ is removed in 80 minutes
<h2>Answer:</h2>
(a) 3.18Ω
(b) 3.18Ω
<h2>Explanation:</h2>Let the two bulbs be A and B
Given;
= Resistance in bulb A = 3.0Ω
= Resistance in bulb B = 2.5Ω
Since the two bulbs are connected in parallel;
i. their effective resistance () is given by
=
+
---------------(i)
Substitute the values of and
into equation (i)
=> =
+
Solve for
= 1.36Ω
ii. voltage (potential difference), V, across them is the same;
Therefore we can get the total current (I) that will flow through them if the voltage to be supplied is 2.4V.
Use the Ohm's law;
V = I x R -----------------(ii)
Where;
V = voltage across them = 2.4V
I = total current flowing through them
R = their effective resistance = = 1.36Ω
Substitute these values into equation (ii) as follows;
2.4 = I x 1.36
I = 2.4 / 1.36
I = 1.76A
(a) Now get the value of R
Since the voltage across the two bulbs is 2.4V out of the 8.0V supplied by the source, then the remaining (8.0 - 2.4 = 5.6)V will pass across the resistor R.
Also, since the two bulbs make a series connection with the resistor R, the same total current (I = 1.76A) that flows through these bulbs will flow through the resistor R.
Therefore, to get the value of R, we use the relation
V = I x R ------------------------------(iii)
Where;
V = voltage across the resistor = 5.6V
I = current through the resistor = 1.76A
<em>Substitute these values into equation (iii)</em>
=> 5.6 = 1.76 x R
=> R = 5.6 / 1.76
=> R = 3.18Ω
Therefore, the value of R to be chosen in order to supply each bulb with a voltage of 2.4V is 3.18Ω
(b) The potential difference and voltage across refer to the same thing. Therefore, the value of R that would make the potential difference across each of the bulbs be 2.4V is the same as the one calculated in (a) which is 3.18Ω
Answer:
<em>When a moving car brakes to a stop the </em><em>kinetic energy of the car is converted to heat energy. </em>
Explanation:
A moving car has kinetic energy.
It is given by the equation
Where m denotes mass of the car and v denote sits velocity. When the brakes are applied the velocity becomes zero and the car doesn’t possess kinetic energy anymore.
According to law of conservation of energy can neither be created nor be destroyed but can only be transformed from one form to another. On coming to a stop, the kinetic energy of the car gets converted to heat. The friction between the tyre and the road heats up the tyre.