Answer:
4 A
Explanation:
The relationship between current, voltage and resistance in a circuit is given by Ohm's law:
where
V is the voltage
R is the resistance
I is the current
The equation can also be rewritten as
from which we see that the current is inversely proportional to the resistance, R.
In this problem, the initial current is I = 8 A. Then the resistance is doubled:
R ' = 2R
So the new current is
so the current is halved.
The force is 2.0 N east
Explanation:
The impulse exerted by a force is defined as the product between the force itself and the time interval during which the force is applied. Mathematically, it is equal to the change in momentum experienced by the object on which the force is acting:
Where
I is the impulse
F is the force
is the time interval during which the force is applied
is the change in momentum
In this problem,
is the time interval
(east) is the impulse
Therefore, the magnitude of the force is
And the direction is the same as the impulse (east).
Learn more about impulse and change in momentum:
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Explanation:
1. study of conversion of heat to mechanics → thermodynamics
A branch of physical science which deals with heat and other forms of energy.
2. The Law of Conservation of Energy → first Law of Thermodynamics
Energy cannot be created nor be destroyed. According to first law of thermodynamics total energy of the system is always constant.
3. Result of applied energy → work
Work is the way of system to release its energy.
4. Principle that states that in any energy transformation some energy is dissipated as heat → Second Law of Thermodynamics
5. energy of motion → kinetic energy
Kinetic energy is defined as energy possessed by the body due to its motion.
6. work/displacement → force
Work is product of force and displacement.
7. power · time → energy
Power is defined energy per unit time.
8. Device that transforms heat energy into mechanical energy → heat engine
heat engine is a device which converts the heat energy which is released due to combustion of fuel into a useful work that is mechanical energy.
9 . Energy due to position → potential energy
Potential energy is defined as energy possessed by the body due to its position.
10. efficiency of a heat engine unit of heat → calorie
11. Measure of molecular motion → Temperature
Kinetic energy is directly proportional to temperature.
Greater the motion more will be the kinetic energy and with more will be the temperature.
12. Heat given off by a liquid with no change in temperature → latent heat of fusion
Latent heat of fusion is defined as heat released by 1 mole of substance when it under goes phase change that is from solid to liquid.
13. Motion within solids → vibrational motion
Vibrational motion is the motion in which particle oscillates from its mean position.
14. Phase of matter on the sun → plasma
Plasma is hot ionized gas with equal number of positive and negative ions. Due to high temperature of sun most the gas are in the plasma state.