Midterm physics

The lowest temperature possible in nature is

-273 degrees C

When we talk about electric power we're talking

-joules per second. -watts

Absolute zero corresponds to a temperature of

0 K and -273 C

A bullet fired horizontally hits the ground in 0.5 s. If it had been fired with twice the velocity it would have hit the ground in

0.5s

The force of gravity acts on all apples on an apple tree. Some apples are twice as far from the ground. Such twice-as-high apples of the same mass, have

1/4 the weight

A woman who normally weighs 400 N stands on top of a very tall ladder so she is one Earth-radius above Earth's surface. What is her weigh there?

100 N

The temperature of boiling water is

100 degrees C or 212 degrees F 373.15 K

Two charges separated by 1 m exert a 1.0-N force on each other. If the charges are pushed to 0.25-m separation, the force on each charge will be

16N

If a projectile is fired straight up at a speed of 10 m/s, neglecting air resistance, the time it takes to reach the top of its path is

1s

When a battery does 24 J of work on 10 C of charge, the voltage it supplies is

2.4 V=w/c

A volume of helium gas has a temperature of 10°C. The same gas twice as hot has a temperature of

20 degrees c

The electric power of a lamp that carries 2 A at 120 V is

240 P=VxI

A length of wire has resistance R. The same wire twice as long has resistance

2R

The electric force on a 2-C charge is 60 N. How great is the electric field at the charge location?

30c

What would be the temperature of 50 g of 20°C water mixed with 80 g of 40°C water?

32.3

The temperature of melting ice is

32°F and 0°C

If the masses of two planets triples and the distance between reduces by half, the force between them would be

36 times as much

Two charges separated by 1 m exert a 1-N force on each other. If the magnitude of each charge is doubled, the force on each charge will be

4

A ball is thrown horizontally from the top of a tall cliff. Three seconds later, the ball has fallen a vertical distance of

45m

A projectile is launched straight upward at 50 m/s. If air resistance is negligible, its speed upon returning to its starting point is

50

What is the force of gravity on a 500-N woman standing on Earth's surface?

500 N

Increasing the temperature of 50 grams of water by 1°C requires

50cal

A stone is thrown horizontally from the top of a cliff. One second after leaving your hand it drops a vertical distance of

5m

The direction of an electric field is defined as the direction of force on a

A positively charged particle

As entropy in a system increases, energy within the system

Becomes less ordered

A hunter fires a bullet from a horizontally-held rifle while simultaneously dropping another bullet from the side of the rifle. Which bullet hits the ground first?

Both

The specific heat capacity of aluminum is more than twice that of copper. Place equal masses of aluminum and copper wire in a flame and the wire to heat up quickest will be

Copper

If Earth's mass decreased to one-half its original mass with no change in radius, your weight would

Decrease to one half

If your mass remained the same while the mass of Earth doubled while staying the same size, your weight would

Double

The electric field around an isolated electron has a certain strength 1 cm from the electron. The electric field strength 2 cm from the electron is

E=KQ/r^2 =E/4 None

Two charged particles repel each other with a force F. If the charge on one particle is doubled and the distance between them is doubled, the force will be

F/2

Which law of thermodynamics is a restatement of the conservation of energy as it applies to thermal systems?

First law (heat added = increase internal energy + external work done by the system)

A charge of 12. C passes through an electroplating apparatus in 2.0 min. What is the average current?

I=Q/t (convert to seconds) 120

What potential difference is required to cause 2.0 A to flow through a resistance of 8.0 Ω?

I=V/R V=IR 16v

If the mass of Earth somehow increased with no change in radius, your weight would

Increase

If the radius of the Earth somehow decreased with no change in mass, your weight would

Increase

If you heat a copper wire its electric resistance

Increases

Two objects move toward each other due to gravity. As the objects get closer and closer, the force between them

Increases

If the Sun were twice as massive,

It's pull on Earth would double and the pull of Earth on the Sun would double

To say that an object is electrically polarized is to say

Its charges have been rearranged

Compared to a single lamp connected to a battery, two identical lamps connected in series to the same battery will draw

Less current

Whether one object is warmer than another object has most to do with

Molecular kinetic energy

Compared to a single lamp connected to a battery, two lamps connected in parallel to the same battery will draw

More current

At some point between Earth and the Moon, the forces due to gravity on a space traveler would be the same. This point is

Near the moon

The power dissipated in a 4-ohm resistor carrying 3 A is

P-I^2xR 36

A power line with a resistance of 2 ohms draws a current of 80 A. The power dissipated in the line is

P=I^2xR 12800

What is the power rating of a device that draws 0.8 A when connected to 120 V?

P=IxV 96

How much current is in a 60-W light bulb connected to 120 V?

P=IxV I=0.5

The current in a 100-W bulb connected to a 120-V source is

P=IxV I=0.8

A pair of 60-W and 100-W incandescent lamps are intended for 120-V operation. Which lamp draws more current?

P=V^2/R R=V^2/P 100 because it has less resistance

A pair of 60-W and 100-W incandescent lamps are intended for 120-V operation. Which lamp has a larger resistance?

P=V^2/R R=V^2/P 60 has the largest resistance

A certain bulb with a resistance of 95 ohms and labeled "150 W" is designated for use in a

P=V^2/R V=(square root)RxP 120

As you comb your hair, electrons are rubbed onto the comb, which becomes

Positively charged

When you remove electrons from a metal cup, the cup becomes

Positively charged

Increasing the temperature of 80 grams of water by 2°C requires

Q=MCT 160 cal

When the distance between two charges is halved, the electric force between the charges

Quadruples

The length of a certain wire is kept same while its radius is doubled. What is the change in the resistance of this wire?

R=(resistivity)xLength/(pi)r^2 reduced by a factor of 4

Roll a bowling ball off the edge of a table. As it falls, its horizontal component of motion

Remains constant

Which law of thermodynamics addresses the direction of heat flow?

Second law (Heat never spontaneously flows from a cold substance to a hot substance.)

For each degree a volume of air at 0°C is cooled, its volume

Shrinks by 1/273

If the masses of two planets doubles and the distance between them also doubles, the force between them would be

The same

A very massive object A and a less massive object B move toward each other under the influence of gravity. Which force, if either, is greater?

The same according to newton's third law

A piece of iron and a cup of water both have the same temperature. If they are heated so the thermal energy of each doubles,

The water will have the higher temperature. lower heat capacity

A projectile is fired horizontally. With no air resistance it maintains its horizontal component of velocity because

There is no horizontal force

Two lamps, one with a thick filament and one with a thin filament, are connected in series to a battery. The voltage is greater across the lamp with the

Thin filament

Which law of thermodynamics states that no system can reach absolute zero?

Third law

The motion of molecules that most affects temperature is

Translation

An Earth satellite is simply a projectile freely falling around the Earth.

True

If the same quantity of heat is added to both a 1-liter and a 2-liter container of water, the temperature change of water in the 1-liter container will be

Twice

Consider two planets in space that gravitationally attract each other. If the mass of one planet is doubled, and the distance between them doesn't change, then the force between them is

Twice as much

Consider two planets in space that gravitationally attract each other. If the masses of both planets are doubled, and the distance between them doesn't change, then the force between them is

Twice as much

Compared to the mass of a proton, the mass of the electron is

Very much less

Inside a freely falling elevator your

Weight is Zero

The electric resistance of a superconductor is

Zero

In the vacuum of outer space, there is no

atmospheric pressure

A rock is thrown upward at 50° with respect to the horizontal. As it rises, its vertical component of velocity

decreases

When the distance between two stars doubles, the force between them

decreases by 1/4

A positive ion has a deficiency of

electrons

According to Newton, the greater the masses of interacting objects, the

greater the gravitational force between them.

If the Earth had twice its present radius and twice its present mass, what would happen to your weight?

half

When the distance between two stars decreases by half, the force between them

increases four times as much

The length of a certain wire is doubled while its radius is kept constant. What is the change in the resistance of this wire?

it doubles

The greatest expansion of water occurs when

it turns to ice

Heat energy is measured in units of

joules and calories

At absolute zero, a substance has

no more energy to give up

A difference between an insulator and a conductor is that a conductor has more

nothing

Which is the smallest unit of measurement for temperature?

one farenheit

The nucleus of an atom is charged

positively

A pair of positively-charged plastic straws tend to

repel

Heat is thermal energy that flows due to

temperature differences

Heat is thermal energy that matter

transfers

A metal ring with a gap in it is shaped like the letter C. When heated, the gap becomes

wider