Answer
current density is given by
where J = σ E
now,
a) Electric field strength at the inner surface of an iron cylinder
a = 0.5 cm = 0.005 m b = 2.3 = 0.023
L = 10 cm = 0.1 m I = 27 A
E = 8.59 x 10⁻⁴ V/m
b) Electric field strength at the outer surface of an iron cylinder
a = 0.5 cm = 0.005 m b = 2.3 = 0.023
L = 10 cm = 0.1 m I = 27 A
E =1.87 x 10⁻⁴ V/m
An object of mass m attached to a spring of force constant k oscillates with simple harmonic motion. The system's potential energy when kinetic energy of (3/4) E is (1/8) k A².
<h3>What is mechanical energy?</h3>
Mechanical energy is the sum of potential energy and kinetic energy.
Total mechanical energy = P.E max = K.E max
Total mechanical energy = K.E +P.E
Given is the kinetic energy is (3/4)E.
E= (3/4)E + P.E
P.E = (1/4) E
Maximum potential energy =E = (1/2) k A²
Here. A is the maximum displacement and k is the spring constant.
The potential energy at kinetic energy of (3/4) E is
P.E = (1/4)E = (1/8) k A²
Therefore, the system's potential energy when kinetic energy of (3/4) E is (1/8) k A².
Learn more about mechanical energy.
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Answer: That's air resistance.
Explanation: Well, air resistance is an upward force exerted on falling objects.
( I hope this helped <3 )
Answer:
Explanation:
The correct answer is right
The distance covered by car is equal to (assuming it is moving by uniform motion) the product between the car's speed and the time of the car ride, 4 h:
where
is the car's speed
is the duration of the car ride
Similarly, the distance covered by train is equal to the product between the train's speed and the duration of the train ride, 7 h:
The total distance covered is S=255 km, which is the sum of the distances covered by car and train:
which becomes
(1)
we also know that the train speed is 5 km/h greater than the car's speed:
(2)
If we put (2) into (1), we find
and if we solve it, we find
So, the car speed is 20 km/h and the train speed is 25 km/h.
