Physical science freshman year

What term describes a statement that has been repeatedly tested and confirmed through observation and experimentation?

Theory

What is a hypothesis?

A possible explanation for an observation

Which step comes first in the scientific method?

Observe and ask a question

Which conversion is correct?

1 kg = 1000 g

Does a scientific theory have the same certainty as a scientific law?

False

Does a measurement of 150 cm equal 1.5 meters?

True

Can temperature in Kelvin be negative?

False

What is the formula for converting Celsius to Fahrenheit?

F = (C × 9/5) + 32

Convert 150 cm to meters.

1.5 m

Convert 2.33 kg to grams.

2330 g

Convert 3.2 kW to watts.

3200 W

Convert 50°C to Fahrenheit.

122°F

Convert 100°C to Kelvin.

373 K

What is momentum defined as?

Mass × Velocity

Which of Newton's Laws explains why you move backward when jumping off a boat?

Newton's 3rd Law

What is inertia?

The tendency of an object to resist a change in motion

Which formula helps you find acceleration?

a = Δv / t or a = F / m

Which law states, 'An object in motion stays in motion unless acted on by a net force'?

Newton's 1st Law

Does friction always oppose motion?

True

If a net force acts on an object, must it accelerate?

True

Is the SI unit for force the Joule?

False

Does greater mass result in greater inertia?

True

Is momentum conserved in collisions?

False

What was Tom's velocity if he ran the 100 meter dash in 12.0 seconds?

8.33 m/s

What is the acceleration of an object that decreases its speed from 35 m/s to 18 m/s over 1.8 seconds?

-9.44 m/s²

What is the final velocity of an object moving at 44 m/s that speeds up by 2 m/s² for 3 seconds?

50 m/s

What is the acceleration of a bicycle and rider weighing 140 kg with a force of 3,500 N?

25 m/s²

What is the force applied to a box with a mass of 15 kg accelerated at 10.2 m/s²?

153 N

What is the mass of a car needing 17,000 N to accelerate at 6 m/s²?

2,833.33 kg

If a ball is rolling with positive velocity and positive acceleration, what is happening to its motion?

The ball is speeding up in the positive direction

Where is an object that starts at 10.0 meters with velocity -1 m/s after 3 seconds?

7 meters

Define friction in your own words.

Friction is the force that opposes motion between two surfaces that are in contact.

State Newton's 3rd law of motion.

For every action, there is an equal and opposite reaction.

What is the energy of motion called?

Kinetic Energy

Where is elastic potential energy stored?

Objects that are stretched or compressed

What does the law of conservation of energy state?

Energy cannot be created nor destroyed, only transformed

How is power defined?

Energy per unit time

Which machines could lose efficiency from friction and heat?

All of the above (A car engine, Pulley system, Bicycle)

Can no machine be 100% efficient?

True

Can energy be created but not destroyed?

False

What is the formula for work?

W = Fd

What is mechanical advantage?

The ratio of output force to input force

What does kinetic energy depend on?

Mass and velocity

State the Law of Conservation of Energy in your own words.

Energy can't be created or destroyed, only changed in form.

Name three ways a machine might lose efficiency.

Friction, heat loss, and sound loss.

What work did Maggie do if she applies 21 N to move a box 6 meters?

126 J

What's the efficiency (percent) of the pulley system if Diane does 45 J of work and gets 36 J out?

80%

What is the kinetic energy of a pendulum moving at 10 m/s with a mass of 5 kg?

250 J

What power is produced by an engine that produces 8,000 J in 40 s?

200 W

What is Mark's gravitational potential energy if he stands on a diving board 3 meters above water and weighs 120 kg?

3,528 J

What could happen to the energy lost in a machine?

It may be converted to heat, sound, or vibration.

What's the mechanical advantage if the input force to a lever is 50 N and the output force is 150 N?

3

What is the formula for gravitational potential energy?

GPE = mgh

What is the flow of electric charge called?

Current

Which device converts mechanical energy into electrical energy?

Turbine

What must a moving magnetic field have?

Change or motion

What happens if you increase the number of loops on a coil in an electromagnet?

Strengthen the field

What happens in a series circuit if one bulb goes out?

All bulbs go out

Does an insulator allow current to flow easily?

False

Does direct current flow in only one direction?

True

Does a parallel circuit have a single path for current?

False

Can a transformer change voltage in a circuit?

True

Does the resistance in a wire increase as the wire gets longer?

True

Name one way to strengthen an electromagnet.

Increase the current or add more wire coils.

How can you lower resistance in a circuit?

Use a thicker wire, use a shorter wire, or use a better conductor.

What unit measures resistance?

Ohm (Ω)

What is Ohm's Law?

V = IR

What's the current at a voltage of 6V and a resistance of 2Ω?

3 A

What is the resistance at 4V and 2A using Ohm's Law?

2 Ω

What is the predicted current at 12V through a 2Ω resistor?

6 A

How much current is drawn by a circuit using 120V to power a 10Ω object?

12 A

What voltage is needed for a 1.2Ω device that draws 60A?

72 V

What current is drawn by a 2.4 kW device running on 240V?

10 A

What happens in a parallel circuit if one light goes out?

The other lights stay on.

What is the total resistance for resistors R1 = 2Ω and R2 = 3Ω connected in series?

5 Ω

What is the total resistance for R1 = 2Ω and R2 = 4Ω in parallel?

1.33 Ω

What is a magnetic domain?

A region where the magnetic fields of atoms are aligned.

What do transformers do?

Change the voltage of alternating current.

What is the input voltage if a transformer has 150 turns in and 200 turns out with an output voltage of 12V?

9 V

How many turns out does a transformer have if it has 120V in, 250 turns in, and 12V out?

25 turns

What type of current do power lines use for long-distance transmission?

Alternating current (AC)

What does it indicate if a field line forms a closed loop?

The field is continuous with no start or end.

What is a circuit diagram?

A visual representation of an electrical circuit.

Which statement is correct regarding energy transformations in a light bulb?

Electrical energy is transformed to light and heat.

What happens to the current if voltage increases and resistance stays the same?

Current increases.

What happens in a closed circuit?

Electricity flows.

Why do transformers only work on alternating current?

AC allows for changing magnetic fields.

What is a function of a turbine?

Convert kinetic energy to electrical.

Is voltage the potential difference between two points?

True

Is resistance in a series circuit the sum of all resistors?

True

Does alternating current reverse direction periodically?

True

Is power measured in watts?

True

Do circuit breakers and fuses protect homes from electrical overload?

True

What is the current if a light bulb operates at 60 W in a 120 V circuit?

0.5 A

What current is drawn by a 900 W microwave using a 120 V circuit?

7.5 A

How much energy is used in kilowatt-hours if a device uses 1500 W in 1 hour?

1.5 kWh

What is the relationship between voltage, current, and resistance?

Voltage = Current × Resistance (Ohm's Law)

Why is electrical energy consumed in homes measured in kilowatt-hours instead of joules?

Kilowatt-hours are a more convenient unit for billing and understanding household consumption.