CTCS Science final

Dragging a log 20 m by hand requires the same amount of work as dragging the log 20 m with a tractor.

True

The mechanical advantage of machines allows them to produce more work than the work put into them.

False

A knife has a higher mechanical advantage than an ax.

False

A screw with a steep thread requires more force than a screw with a shallow thread.

True

A force that tries to rotate an object around its axis

Torque

The measure of a machine’s ability to convert energy from one form to another

Efficiency

The ratio of input distance to output distance

Ideal Mechanical Advantage

The ratio of output force to input force

Actual Mechanical Advantage

The measure of the amount of work done per second

Power

The energy transferred when a force moves an object

Work

A wheel and axle with a cable in a groove around the perimeter of the wheel

Pulley

A screw is a modified

Inclined plane

Best example of kinetic energy

An avalanche flow

The kinetic energy of a 75 kg sprinter running at 8.7 m/s

2838 J

The sum of all forms of kinetic and potential energy in a system

Mechanical energy

The formation of coal requires organisms to be buried and compressed.

True

Two disadvantages of using nuclear energy

Radioactive waste and dangerous accidents/radiation

Electrical energy generated by moving water

Hydroelectric energy

Thermal energy from deep within Earth

Geothermal energy

Average kinetic energy of particles

Temperature

Two objects transfer thermal energy until

They have the same temperature

Rising hot air in a balloon demonstrates

Convection

Heat lamps keeping food warm demonstrate

Radiation

The heat required to melt a solid

Heat of fusion

The idea that heat comes from constant particle motion

Kinetic-molecular model

Conduction requires two objects to be in contact.

True

Energy naturally flows from cold objects to warm objects.

False

Energy cannot be created or destroyed

First law of thermodynamics

The sum of the kinetic energy of all particles in an object

Thermal energy

Zero on the Kelvin scale

Absolute zero

The transfer of thermal energy

Heat

Thermal energy transfer through electromagnetic waves

Radiation

Rubber does not allow thermal energy to move through easily.

Insulator

As force increases on a given area, pressure

Increases

Archimedes’ principle describes

Relationship between displacement and buoyant force

Most liquids become less viscous as temperature increases.

True

An 820 N man exerts 222.2 Pa on the floor. Contact area?

3.69 m²

What happens when a balloon of gas is heated?

Particles move faster and spread apart

Periodic motion

Motion that repeats in equal time intervals

When a spring system reaches equilibrium position

Kinetic energy is maximum

Simple harmonic motion restoring force is proportional to displacement.

True

In a transverse wave, the disruption moves

Perpendicular to wave travel

An ocean wave is an example of a

Surface wave

A tree trunk appears bent underwater because of

Refraction

The bending of waves through an opening

Diffraction

After two waves collide, they

Move on unaffected by each other

Amplitude

Maximum displacement from equilibrium

Crest

Highest point of a wave

Equilibrium position

Resting position of the medium

Trough

Lowest point of a wave

Wave height

Distance from crest to trough

Wavelength

Distance between matching points on a wave

A sound wave is a good example of a longitudinal wave.

True

A reflected wave has less energy than before reflection.

True

The time to complete one cycle

Period

A driving force causing larger amplitudes results in

Resonance

Regions of high density and pressure in longitudinal waves

Compressions

When a crest coincides with a trough

Destructive interference

The crests and troughs of a standing wave

Antinodes

Wavelength of middle C (261.63 Hz, 343 m/s)

1.31 m

If a wave period is 2.64 s, frequency equals

0.38 Hz

Which does NOT affect how fast sound travels?

Direction the sound waves travel

A sound’s pitch is related to its

Frequency

Difference between the same note on clarinet vs trumpet

Timbre

How many times greater is 130 dB than 100 dB?

1000 times greater

Difference between loudness and intensity

Intensity is actual sound energy; loudness is human perception

Rank sound speed from fastest to slowest

Solids → liquids → gases

What type of wave is a sound wave and why?

Mechanical longitudinal wave because it requires a medium

You can quadruple electric force by

Doubling the charge of both objects

A positively charged glass rod rubbed with silk became charged because

The rod lost electrons to the silk

Which charging process results in oppositely charged objects?

Charging by induction

Current flowing in one direction

Direct current

Unit for electrical potential difference

Volt

Circuit symbol shown

Open switch

Current must flow through every component in a

Series circuit

If one bulb burns out and another stays lit, the circuit is

Parallel circuit

A laser printer uses static electricity.

True

The ideal circuit arrangement for house wiring would be a series circuit.

False

Electric potential difference

Voltage

Material through which charge flows poorly

Electrical insulator

The degree to which a material slows charge flow

Resistance

Flow of electric charge that changes direction repeatedly

Alternating current

Flow of charge through a complete circuit

Electric current

Unit of electric charge

Coulomb

Unit of electric current

Ampere

Unit of resistance

Ohm

In electric field models, field lines point toward

Negatively charged objects

Unlike static electricity, current electricity involves ______ electric charges.

Moving

Current electricity moving in one direction

Direct current

Materials through which electric charge moves easily

Electrical conductors

Current taking an unintended path

Short circuit

One source of DC power and one source of AC power

Battery and home electricity

Current in a circuit with 8.9 V and 3.6 Ω

2.47 A