Answer:
The internal resistance of the cell is 0.051 ohm.
Explanation:
Given;
emf of the battery, E = 12 V
terminal voltage of the cell, V = 8.2 V
current in the circuit, I = 75 A
let the potential drop of the cell due to internal resistance (r) = Ir
The internal resistance of the cell is calculated from the equation below;
E = V + Ir
where;
r is the internal resistance of the cell
Therefore, the internal resistance of the cell is 0.051 ohm.
Answer:
A. Nuclear fusion requires very high pressures and temperatures.
Explanation:
Answer:
C. her moment of inertia increases and her angular speed decreases
D. her moment of inertia increases and her angular speed decreases
Explanation:
The moment of inertia of a body is the sum of the products of an increment of mass and the square of its distance from the center of rotation. When a spinning person extends her arms, part of her mass increases its distance from the center of rotation, so increases the moment of inertia.
The kinetic energy of a spinning body is jointly proportional to the moment of inertia and the square of the angular speed. Hence an increase in moment of inertia will result in a decrease in angular speed unless there is a change in the rotational kinetic energy.
This effect is used by figure skaters to increase their spin rate by drawing their arms and legs closer to the axis of rotation. Similarly, they can slow the spin by extending arms and legs.
When the person extends her arms, her moment of inertia increases and her angular speed decreases.
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<em>Note to those looking for a letter answer</em>
Both choices C and D have identical (correct) wording the way the problem is presented here. You will need to check carefully the wording in any problem you may think is similar.
Answer:
-20 kg.m/s
Explanation:
We have an object moving at 5 m/s with mass 5 kg. The initial momentum is:
pi = m × vi
pi = 5 kg × 5 m/s = 25 kg.m/s
It undergoes a quick collision with some other object and now moves at 1 m/s. The final momentum is:
pf = m × vf
pf = 5 kg × 1 m/s = 5 kg.m/s
The change in the object's momentum is:
Δp = pf - pi
Δp = 5 kg.m/s - 25 kg.m/s = -20 kg.m/s