Physics 4th Weeks Review 2

Physics 4th Weeks Review

By Stacy King

Fill in the Blanks

In a physics lab, a 0.500-kg cart (Cart A) moving with a speed of 129 cm/s encounters a magnetic collision with a 1.50-kg cart (Cart B) that is initially at rest. The 0.500-kg cart rebounds with a speed of 45 cm/s in the opposite direction. Determine the post-collision speed of the 1.50-kg cart.

Inelastic Collision Equation

Multiple Choice

The diagram shows a 2 kg box travelling at 3 m/s colliding with and sticking to a second box on a frictionless surface. The resultant velocity of the two boxes combined is 1 m/s. What is the mass of the second box, to the nearest kilogram?

• 4.0 kg

• 3.0 kg

• 0 m/s

• 1 m/s

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​A measurement that describes the average kinetic energy in random thermal motion per atom or molecule

​Temperature

Multiple Choice

What happens to particles when they are heated?

• They speed up and spread out
• They slow down and compress
• They stop moving
• They move closer together and speed up

A calibration tool to measure temperature changes

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3 different scales

Fa​hrenheit

Celsius

​Kelvin- the base unit of temperature in the International System of Units, having the unit symbol K

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​Thermometers

The more disorganized the molecules are the higher state of entropy- the measure of disorder in a system

Entropy increases as temperature increases​

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​Entropy and States of Matter

Multiple Choice

Entropy is a measure of

• heat energy

• temperature

• the disorder/randomness of a system

All kinetic energy stops

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the minimum possible

temperature, 0 K, or −273ºC (−459ºF)

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​Absolute Zero

Multiple Choice

What happens at absolute zero?

• All Motions cease

• everything turns to a solid

• everything dies

• who knows?

0th Law

​Thermal equilibrium

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The condition under which two substances in physical contact with each other exchange no heat energy

temperatures balance out, heat stops flowing, then the system (or set of systems)​

Laws of Thermodynamics

Multiple Choice

If A has the same temperature as B and C. B and C are in thermal equilibrium. Which law does this refer to?

• 0th law of thermodynamics

• 1st law of thermodynamics

• 2nd law of thermodynamics

• 3rd law of thermodynamics

1st Law

Conservation of Energy

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Energy cannot be created or destroyed only changed into another form ​

Laws of Thermodynamics

Multiple Choice

While running your kinetic energy converts to thermal energy. Which law does this refer to?

• 0th law of thermodynamics

• 1st law of thermodynamics

• 2nd law of thermodynamics

• 3rd law of thermodynamics

2nd Law

Heat

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Heat always flows from hot to cold

Laws of Thermodynamics

Multiple Choice

Thermal energy always moves:

• From a high temperature object to a lower temperature object.
• From a lower temperature object to a higher temperature object.
• From an object with lower kinetic energy to an object with higher kinetic energy.
• From an object of higher mass to an object of lower mass.

3rd Law

Entropy

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​As temperature approaches absolute zero, entropy is at constant minimum

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Laws of Thermodynamics

Multiple Choice

What would be the effect on the particles if more heat is supplied to the system?

• They would slow down
• They would stop moving
• They would speed up
• There would be no effect

Conduction- heat transfer through solids

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Convection- heat transfer through liquids and gasses

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Radiation- heat transfer through electromagnetic waves​

HEAT Transfer

Multiple Choice

What method of heat transfer is occurring in the pot?

• Convection

• Conduction

• Radiation

Multiple Choice

What method of heat transfer is this?

• Convection

• Radiation

• Conduction