PHYSICS
HIGH SCHOOL

Answer: Resistance = (voltage) divided by (current)

Resistance = (100 volts) / (10 Amperes) = 10 ohms

Resistance = (100 volts) / (10 Amperes) = 10 ohms

HIGH SCHOOL

A speed skater moving across frictionless ice at 8.30 m/s hits a 5.10-m-wide patch of rough ice. She slows steadily, then continues on at 5.20 m/s ?

Incomplete question.The complete question is here

A speed skater moving across frictionless ice at 8.30 m/s hits a 5.10m wide patch of rough ice. She slows steadily, then continues on at 5.20 m/s.What is her acceleration on the rough ice?

Answer:

acceleration = -4.103 m/s²

Explanation:

Given data

Initial velocity Vi=8.30 m/s

Final velocity Vf=5.20 m/s

Initial distance xi=0 m.......(We choose xi=0 the start point of acceleration motion )

Final distance xf=5.10 m

To find

Acceleration

Solution

From the kinetic equation

MIDDLE SCHOOL

I. A car travels at uniform velocity a distance of 100m in 4 seconds. What is the velocity of the car?

Answer:

400 meters

Explanation:

COLLEGE

Pumping of groundwater in California most effectively: Select one: a. Causes sediments in aquifers that are emptied to compact and the ground above it to sink

b. Promotes rejuvenation of the groundwater resource via lateral groundwater flow

c. Decreases water reserves in Hetch Hetchy reservior in the Sierra Nevada

d. Is necessary due to reduce flooding over subsided areas and protect infrastructure

e. All of these

Answer:

A

Explanation:

Ans- A, causes sediments in aquifers that are emptied to compact and the ground above it to sink.

This is one of the major problems for California nowadays. Due to excessive groundwater pumping to satisfy the demand of huge population the aquifers are drying, hence compacting and for that the land above sinks.

HIGH SCHOOL

Object A attracts object B with a gravitational force of 10 newtons from a given distance. If the distance between the two objects is doubled, what is the changed force of attraction between them? A. 2.5 newtons

B. 5 newtons

C. 20 newtons

D. 100 newtons

By definition, the gravitational force is given by:

Where,

G: gravitational constant

m1: mass of object 1

m2: mass of object 2

r: distance between objects:

We know that the force is equal to 10N:

If the distance is double we have:

Therefore, the new force is:

2.5 newtons

Answer:

the changed force of attraction between them is:

A. 2.5 newtons

2.5

(Because formula has r squared, or 2 times 2 or 4)

So 10:4=2.5

(Because formula has r squared, or 2 times 2 or 4)

So 10:4=2.5

HIGH SCHOOL

The velocity of sound on a particular day outside is 331 meters/second. What is the frequency of a tone if it has a wavelength of 0.6 meters? 5.52 × 102 hertz

2.56 × 102 hertz

459 × 102 hertz

675 × 102 hertz

990 × 102 hertz

Answer:

Hz

Explanation:

For a wave, the relationship between velocity, wavelength and frequency is given by the wave equation:

where

v is the velocity

f is the frequency

is the wavelength

For the sound wave in this problem, we have:

v = 331 m/s

Solving the equation for f, we find the frequency:

HIGH SCHOOL

Manmade global warming is caused by _______.

Human activity--such as burning fossil fuels--causes more greenhouse gases to build up in the atmosphere. As the atmosphere "thickens" with more greenhouse gases, more heat is held in. Fossil fuels such as oil, coal and natural gas are high in carbon and, when burned, produce major amounts of carbon dioxide or CO2.

Answer:

pollution

Explanation:

im taking the test

MIDDLE SCHOOL

When you talk about a battery's voltage, you are referring to

How powerful it is :)

HIGH SCHOOL

25 PTS Which of these is NOT equal to a joule of energy?

A. N-m

B. kg-m2/s2

C. kg2-N/s

D. All of these are different ways of writing a joule.

I thought that A was the only way to write a joule of energy, but there is only 1 answer here.

The answer would be C

HIGH SCHOOL

What is the energy of a photon that has the same wavelength as an electron having a kinetic energy of 15 ev?

Answer:

Explanation:

The kinetic energy of an electron is given by the following equation:

(1)

Where:

is the momentum of the electron

is the mass of the electron

From (1) we can find :

(2)

(3)

Now, in order to find the wavelength of the electron with this given kinetic energy (hence momentum), we will use the De Broglie wavelength equation:

(4)

Where:

is the Planck constant

So, we will use the value of found in (3) for equation (4):

(5)

We are told the wavelength of the photon is the same as the wavelength of the electron:

(6)

Therefore we will use this wavelength to find the energy of the photon using the following equation:

(7)

Where is the spped of light in vacuum

Finally: