b. the average kinetic energy of molecules
c. the average potential energy of molecules
d. the direction of the moving molecules in a substance
Temperature measures the average kinetic energy of molecules in a substance.
The correct answer is b. the average kinetic energy of molecules.
Temperature measures the average kinetic energy of molecules in a substance. When the temperature of a substance increases, the molecules move faster and have more kinetic energy. This is why substances generally expand when heated and contract when cooled.
For example, when you heat water, the temperature increases, and the water molecules move faster, eventually reaching a boiling point where they have enough kinetic energy to break the bonds and escape as steam.
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B. weight
C. length
D. temperature
Answer: The correct answer is option B.
Explanation:
Resistance is the property of the material which resists the flow of current.
The expression for the resistance is as follows:
Here, is the density of the wire, l is the length of the wire and A is the area of the cross section of the wire.
The resistance of the wire depends on the length of the wire, area of the cross section of the wire and the temperature.
The thicker wire has less resistance. The thinner wire has more resistance.
The longer wire has more resistance in comparison to the shorter wire in length. The resistance of the wire increases with increase in temperature.
The resistance does not depend on the weight of the wire.
Therefore, the correct option is weight.
the best answer is b
increase by a factor of 4
decrease by a factor of 2
decrease by a factor of 4
Answer:
Increase by a factor of 4.
Explanation:
The acceleration of a car moving with speed v in a circle of radius R is given by:
Now if we double the speed in the equation above, it becomes . Thus:
Therefore the acceleration is increased by a factor of 4.
Answer:
To calculate how many joules of kinetic energy an electric car can have using the 250 joules of stored chemical energy from the battery, you'll need to consider the efficiency of the energy conversion from chemical to kinetic energy. Electric cars are not 100% efficient in converting stored energy to kinetic energy due to losses in the system, including in the motor, transmission, and drivetrain.
Let's say the efficiency of the conversion is "η," where η is a value between 0 and 1 (e.g., 0.85 for 85% efficiency). The kinetic energy (KE) the car can have will be:
KE = η * 250 joules
You can calculate the kinetic energy for different efficiency values by substituting η into the formula.
For example, if the efficiency is 85%:
KE = 0.85 * 250 joules = 212.5 joules
So, with an 85% efficiency, the electric car can have approximately 212.5 joules of kinetic energy from the 250 joules of stored chemical energy in the battery. The actual efficiency may vary depending on the specific car and its components.