PHYSICS
MIDDLE SCHOOL

Mary is correct because molecules are constantly losing kinetic energy no matter what state they are in.

Mary is correct because as the liquid cools, the molecules slow down as they lose kinetic energy.

Ron is correct because kinetic energy is a fixed characteristic of molecules and does not change.

Ron is correct because kinetic energy can only increase, not decrease.

Answer:

Answer:

Mary is correct because as the liquid cools, the molecules slow down as they lose kinetic energy.

Explanation:

The way to identify the temperature of a body, according to common sense, is to use the words hot and cold, but in fact, hot is when the molecules are very agitated, causing an increase in body temperature. The cold is related to the more stationary state of the molecules, the less agitated, the colder the body becomes.

With that, we can say that as the liquid cools, the molecules move less and less, which decreases their kinetic energy, which is the energy related to movement. In this case, Mary is correct because, as the liquid cools, the molecules slow down as they lose kinetic energy.

Answer:

Answer:

Mary is correct because as the liquid cools, the molecules slow down as they lose kinetic energy.

Explanation:

MIDDLE SCHOOL

Help for 25 points. 2. Check all that apply. Electromagnetic waves are:

Mechanical waves

Transverse waves

Pressure waves

Move perpendicular

Move parallel

Frequency is directly related to speed

Frequency is inversely related to wavelength

Wavelength is directly related to speed

Require a medium

Transfer energy

Answer:

Transverse waves

Move perpendicular

Frequency is directly related to speed

Frequency is inversely related to wavelength

Wavelength is directly related to speed

Transfer energy

Explanation:

Electromagnetic waves consist of periodic oscillations of electric and magnetic fields. As all waves, they transfer energy, but not matter,

Electromagnetic waves are transverse waves, which means that they oscillate in a plane perpendicular to the direction of propagation of the wave. The speed, the wavelength and the frequency of electromagnetic waves are related by the following equation:

where

c is the speed (speed of light, which is constant for electromagnetic waves travelling in a vacuum)

f is the frequency

is the wavelength

From this equation we see that:

- The frequency is directly related to the speed

- The wavelength is directly related to the speed

- The frequency is inversely related to the speed

HIGH SCHOOL

A spring gains 2.34 joules of elastic potential energy as it is compressed 0.250 meter from its

equilibrium position. What is the spring constant

of this spring?

(1) 9.36 N/m (3) 37.4 N/m

(2) 18.7 N/m (4) 74.9 N/m

The correct answer to the question is: 4) 74.9 N/m.

EXPLANATION:

As per the question, the stretched length of the spring is given as x = 0.250 m.

The potential energy gained by the spring is given as 2.34 joules.

We are asked to calculate the spring constant of the spring.

The potential energy gained by the spring is nothing else than the elastic potential energy .

The elastic potential energy of the spring is calculated as -

Potential energy P.E =

⇒k =

=

= 74.88 N/m

= 74.9 N/m. [ans]

Hence, the force constant of the spring is 74.9 N/m.

Elastic energy equals 1/2 k(spring constant) *Δx^2(change in position) so you set the energy of the spring equal to the 1/2kΔx^2 and solve for K. 2.34=1/2k(.250)^2 which gives you a spring constant of 74.9 N/m.

MIDDLE SCHOOL

John's truck has more mass than his brother Thomas' truck. John's truck has less inertia

will accelerate more quickly

needs more force to move

is 100 percent efficient

John's truck has more mass than his brother Thomas' truck.

John's truck has more inertia than Thomas' truck.

If both trucks get equal force, John's truck will accelerate more slowly than Thomas' truck.

John's truck needs more force to accelerate.

If both trucks are just sitting there, John's truck needs more force to start moving.

We don't know anything about the efficiency of either truck. Or the efficiency of either brother, for that matter.

HIGH SCHOOL

Which happens to the magnetic field of a wire when you change the direction of the current in the wire? The magnetic field ______. becomes stronger

also changes direction

becomes weaker

The direction of the magnetic field around a wire depends on

the direction of the current flowing through the wire. When you

change the direction of the current in the wire, the direction of the

magnetic field around it also changes direction.

The current in every electric cord in your house changes its direction

120 times every second. So the magnetic field around every electric

cord in your house also changes its direction 120 times every second.

the direction of the current flowing through the wire. When you

change the direction of the current in the wire, the direction of the

magnetic field around it also changes direction.

The current in every electric cord in your house changes its direction

120 times every second. So the magnetic field around every electric

cord in your house also changes its direction 120 times every second.

MIDDLE SCHOOL

While racing on a flat track a car rounds a curve of 56m radius and instantaneously experiences a centripetal acceleration of 36 m/s how fast was the car going. 25m/s

45m/s

35m/s

2.0 x 10^3 m/s

45m/s should be the answer because the acceleration changes into's velocity and goes towards the centre in which is 56/ms that equals v^2/R the speed at the instant.

Hope this helped

Regards, ShaggySnaps

MIDDLE SCHOOL

a gas powered model airplane has a mass of 2.50 kilograms. A student exerts a force on a cord to keep the airplane flying around her at a constant speed of 18.0 meters per seond in a horizontal, circular path with a radius of 25.0 meters. what is the magnitude of the centripetal force exerted on the air plane to keep it moving in this circular path

The first thing to do in this case is a free-body diagram in the radial direction.From the free body diagram you get that

Fc = m * ar

where

Fc: Centripetal force

m: mass

ar: radial acceleration

By definition

ar: v ^ 2 / r

where

v: speed

r: radio

Substituting the values

Fc = m * (v ^ 2 / r)

Fc = (2.50 * ((18 ^ 2 / (25)) = 32.4N

answer

the magnitude of the centripetal force exerted on the air plane to keep it moving in this circular path is 32.4N

Fc = m * ar

where

Fc: Centripetal force

m: mass

ar: radial acceleration

By definition

ar: v ^ 2 / r

where

v: speed

r: radio

Substituting the values

Fc = m * (v ^ 2 / r)

Fc = (2.50 * ((18 ^ 2 / (25)) = 32.4N

answer

the magnitude of the centripetal force exerted on the air plane to keep it moving in this circular path is 32.4N

MIDDLE SCHOOL

How can waves transport energy without transporting matter from place to place

As waves pass through matter, whether it's a gas, solid, liquid, etc., this matter on a molecular level is displaced (the molecules are displaced) and this translates to kinetic energy.

COLLEGE

Consider a simple ecosystem of a shrub, worm, bird, and soil microbes and identify the producer, primary consumer, secondary consumer, and decomposers. Which of these organisms photosynthesizes? Which carry out cellular respiration? Which give off heat into the surroundings?

Which of these organisms photosynthesizes?

shrub

Which carry out cellular respiration?

shrub, worm, bird, and soil microbes

Which give off heat into the surroundings?

shrub, worm, bird, and soil microbes

shrub

Which carry out cellular respiration?

shrub, worm, bird, and soil microbes

Which give off heat into the surroundings?

shrub, worm, bird, and soil microbes

COLLEGE

An archer pulls her bowstring back 0.396 m by exerting a force that increases uniformly from zero to 237 N. (a) What is the equivalent spring constant of the bow? 598.48 Correct: Your answer is correct. N/m (b) How much work does the archer do on the string in drawing the bow?

Answer:

(a) The equivalent spring constant is 598.485 N/m

(b) The work done is 46.926 J

Explanation:

From Hooke's law of elasticity

K (spring constant) = F/e

F is the range of force exerted = 237 - 0 = 237 N

e is the extension of bowstring = 0.396 m

K = F/e = 237/0.396 = 598.485 N/m

Work done = 1/2 Fe = 1/2 × 237 × 0.396 = 46.926 J