Physics

ResourcesQuestionsPhysics

About energy

Can someone tell me about energy and potential energy

Christel

Acceleration

An object of mass 20kg is falling in air and experiences a force due to air resistance of 40N. Determine the net force acting on the object and calculate the acceleration of the object.

Fareena

Aeroplane Voltage !!

The length of the wing of an air plane is 10 m. Its horizontal velocity is 200 m /s. If the vertical component of the earth’s magnetic field is 5.0 × 10^-5 weber /m2, calculate the potential difference developed across the two ends of the wing.

Aleshia

an L.E.D bike light that produces 95% light and only 5% heat

an L.E.D bike light that produces 95% light and only 5% heat

Yoke

At what distance behind Jenny should Linda be when Jenny starts running?

A track team is practicing for a 4 x 100 m relay race. The first runner, Linda, is running at a constant speed of 8.6 m/s. The next runner, Jenny, will be starting from rest at the 80 m mark. She has an acceleration of 1.0 m/s2. Ideally the two runners meet at the 100 m mark to hand over the baton. At this point, Jenny is still accelerating.

a) At what distance behind Jenny should Linda be when Jenny starts running? (Assume for simplicity that there is no distance between the two runners when the switch happens.)

b) How long does it take Jenny to run from the 80-m mark to the 100-m mark?

c) What’s Jenny’s speed at the 100m mark? Linda Jenny

Jamie

Can Sorter? Electromagnets

I need to know how can sorters works. They pick up steel cans but not aluminium ones. Why?

I need to mention the works like magnetism, electromagnets

Keiron

Can you check my answers regarding ground energy states

Calculate the ground state energy of the B4+ ion (i.e. for n = 1), and the energy of the next four highest energy levels (i.e. for n = 2, 3, 4, 5).

My answers are:- boron z=5

n=1 E1 = -340 eV n=2 E2 = -85 eV n=3 E3 = -37.78 eV n=4 E4 = -21.25 eV n=5 E5 = -13.6 eV

Are these right? thanks for your help.

Rajesh

Carnot Cycle

1kg water closed system -isothermal heat intake process initial pressure 15bar dryness 25%. Then expansion to 1bar and 84.9 dryness. What is heat input and work done at isothermal stage? What is heat intake at beginning of heat rejection process?

Rajkiran

deduce expression for resistance

deduce expression for resistance

Jude

Density

Discribe an experiment you would carry out in order to determinethe density of a stone?

Ria

describe iron

describe iron

Cassandra

describe steel

describe steel

Simona

dimensional analysis

the displacement of an object of mass m after time t when a net force F acts on it is dependent on F, t and m. use dimensional analysis to work out the formula for the displacement of the object.

Camus

does nuclear energy benefits the energy production

does nuclear energy benefits the energy production

Kier

Electricity

could you teach me physics in topic Electricity?

Moira

electromagnets

hey i am doind a piece of homework on electromagnets and i have to reaserch 3 examples and i have already done scrap yard can i have some help?

Nnamdi

Electrostatics

Deduce the expression for the electric field E due to a system of two charges q1 and q2 with position vectors r1 and r2 at a point r with respect to common origin.

Roberta

Force

A hammer head with mass 0.5 kg strikes the head of a nail at a speed of 10m/s .The nail is driven 1 cm into a piece of wood. What is the average force on the nail?

Sukhdeep

force and pressure

The weight of a rider, driving scooter is assumed to be evenly distributed on both the tyres. The area of contact of each type with the ground is 10 cm2. If the pressure inside the tyres is 3 bar, find the mass of the rider (g = 10 ms−2)

Cale

Half Life

i dont understand halflife. I just dont understand the concept but i understand radioactive decay.

Loraine

heat and energy transfer

What can you say about the rate of heat energy transfer in an object that is at the same tempreature as it's surroundings

Mia

heat and energy transfer

why is water used to cool car engines?

Jeri

heat and energy transfer

What is the difference between latent heat of fusion and latent heat of vapourisation?

Erina

heat capacity is measured in what

heat capacity is measured in what

Peter-Daniel

Help with approximation first/second derivative velocity/accel

I have a table of values for a projectile moving away from a radar station. My first column is the time (t) of 0 to 60 with time steps of 4. I then have a distance(km) of the projectile from the radar station followed by the angle(radians) of the projectile to the radar station.

The distance obviously increases by time along with a lowering of the angle of the projectile to the radar station.

I need to write a program which will work out the magnitude of velocity and acceleration for each time step (each 4 seconds upto 60) as the projectile moves away. I am confused how to do this because I am unsure how to approximate the derivatives. I can give further data and formulas if required. The program is the easy bit but I just don't know how to get the write answers into Excel first so I can work out how to program it correctly.

Ossama

Hi I really need help!!!!!!!!

I need to do a presentation on Magnetism. The presentation needs to be enjoyable and informative. Basically I am sposed to teach them but I dunno wat to do. Any ideas?

Wendie

Homework help?

Carol eats a regular hamburger and drinks a glass of cow's milk for breakfast. Suppose that energy content of the hamburger and the milk are 2115 kJ and 565kJ respectively. What % of energy from the food does Carol use to push a sack of rice along a horizontal distance of 4.75 m? Her hands exerted a force of 50N applied 20° down with the horizontal.

Sajid

how do cooling fins work?

I need to know how these work in relation to thermal transfers and the kinetic theory?

Carina

How do I pass an ISA in GCSE science

I have already failed two and another one is coming up soon can you help me?

Sher

how do you pass an ISA

The question paper and experiment don't seem to link?

Keloli

How large is the moon in comparison to the Earth

How large is the moon in comparison to the Earth? And would this have any bearing on our seasons if it was larger?

Finella

i dont get physics D: helpp

  1. Two cars are travelling on a straight stretch of highway at a steady 110 km/h in the same direction. Drivers are advised to maintain a separation of about 3 seconds between cars (more in poor road conditions). How far apart should the two cars be in meters (give you r answer to the nearest meter).

Claudio

I don't understand lenses

How do we know the difference between the lenses. And what is the focal length?

Khairul

if the sun was bigger would it give us more heat

if the sun was bigger would it give us more heat

Aynslie

is sand a solid or a liquid and why?

And now add more detail if you want to.

Rhiona

Looking for a tutor

Hi, my son is a first year undergrad student studying Chemical Engineering. He is having difficulties understanding Fluid Dynamics. Am looking for an online tutor to help him.

Karena

measurement

to find the volume of an irregular shaped wooden piee a sinker made of steel (relative density = 7.85) having a mass of 157 g was used. if the levels of water before and after immersing the sinker wood ombination are 102 ml and 170 ml respectively then find the volume of woodewn piece

Kenny

Measurement and units(Prefixes)

How do you go about converting prefixes? example: 320J______kJ

Alasdair

Mechanics

a small block is pulled along a rough horizontal surface at a constant speed of 3m/s by a constant force. The magnitude of the force is 30N and acts at an angle of 30 degrees to the horizontal. Calculate the work done by this force in 10 seconds

Nassma

Momentum

what does basically momentum mean? what is elastic and inelastic momentum? please, if possible, answer the first question at first.

Rosalind

Moving car

A 1000kg car speeds up on the street at 72km/h. It suddenly brakes with a constant force of 5x103 N. How far the car will travel from the moment it brakes till it completely stops?

Jilly

newtons law

what's live example of newton's 3rd law?

Teri

OCR A level physics - Nuclear physics module

A polonium-210 atom has mass 3.5x10^-25kg and each decay from one of these atoms produces an energy of 5.3MeV. a) How many decays per second are required to supply a power of 1000W? b) What mass of polonium-210 is required for this power? The decay constant of polonium-210 is 5.8x10^-8

Gi

Parallax angle question

if a star is 5.2x1016 meters away, what is the parallax angle in degrees?

Just need a step by step answer to confirm that my answer of 0.000165598290 is correct ( note that the second five and zero have a recurring symbol above each)

I used the conversion 1parsec= 3.1x1016m in my calculation

any help would be much appreciated

Caillin

physics

The following is a summary of a nuclear fission reaction: 235 1 →unknown nucleus A (Equation 1) 92 U On

unknown nucleus A → 90 Sr + unknown nucleus B + 3 1n (Equation 2) 38 O

Can you help find the mass number and atomic number for the unknown nuclei A and B to identify them. can you explain this to me and how you got worked this out, thank you most sicnerely.

I have done some workings but think it may be incorrect

Zakya

Physics

How can we calculate the work done by a tension force a solid at time t ?

Earl

Physics

What is physics

Garwing

Physics

Without using your spring scale, estimate the order of magnitude of the mass of your calculator in grams from what you judge to be its size, using the fact that the density of water is 1 g/cm3. Assume that the density of water is about the same as the density of your calculator. 1 g 102 g 104 g 106 g

Bharatram

Physics ISA

I need an experiment to test this-the output of an solar cell depends on the are of a solabr cell exposed to light. Help anyone? Also need a website with it on. 🙂

Allison

pressure

how does pressure in fuids work?

Antonio

Properties of energy sources

I have been asked to list 6 properties which I think the ideal energy resource should have for generating electricity in a power station. So far I have: Clean and pollution free Efficient allowing the majority of the energy to be harnessed Cheap to source, refine, store and transport Plentiful and renewable Safe to use, store and transport

Do those sound ok so far? I can't think of a 6th one but was considering putting easy to transport to homes but with the question stating that it is for generating electricity in a power station that already accounts for the transport.

Zulehuma

quantum physics

How to find the ground state for electron that is in harmonic potential when the potential is given. I know that you use schödingers equation and wave function, but thats all. Otherwise cant solve it!

Dahni

red shift

I need help on understanding what redshift is and what the charts mean

Perry

Resistance Length ?

What equal lengths of iron wire and a lead wire, each of 1 mm diameter must be joined in parallel to give an equivalent resistance of 2 ohm ? Resistivity of iron and lead are 10 and 49 micro ohm-cm respectively.

Tammy

science - expantion and contraction

  What expands and contracts when getting hotter and colder in your house and garden?

Hanifah

Snowball physics

You are in a snowball fight, and throw a snowball at a high angle over level ground. While your opponent is watching this first snowball, you throw a second one at a low angle timed to arrive before or at the same time as the first one.

Assume both snowballs are thrown with a speed of 39.4 m/s. the first one is thrown at an angle of 71 degrees to the horizontal. What angle should the second snowball be thrown to arrive at the same point as the first?

Zainab

sound wave

my question is- "A around wave of frequency 220 Hz travels along a steel bar. Its wavelength is 25 m. How fast is the wave travelling?"

Nye

Speed

A roller coaster car with a mass of 250kg starts from a height of 100m above the ground just before rolling down the frictionless track. Find the speed of the car as it reaches the ground

Lee-Ann

Speed

Falling objects drop with an average acceleration of 9.8m/sec/sec. If an object falls from a tall building, how long will it take before it reaches a speed of 7m/s?

Vingenza

State the two effects that absorption of electromagnetic radiation can have on the substance that absorbs it

State the two effects that absorption of electromagnetic radiation can have on the substance that absorbs it

Alyssa

stopping distance

what is topping disance

Roseanna

Stress strain graph

A sample of steel was tested under large loads and the following stress strain graph was plotted Calculate the young modulus of the steel

Arianne

Telescope

How does placing telescopes higher eg: in the mountains above weather systems make observing easier?

Annika

vector diagram, magnitude and direction.

In a tug of war, one team pulls to the left with a force of 600 N. The other team pulls to the right with a force of 475 N. Draw a vector diagram showing the forces and what is the magnitude and direction of the resultant force.

Kieron

Vector Unit

Define and give examples of vector units

Wasif

velocity

a javelin is thrown at 20m s-1 at an angle of 45 degrees to the horizontal. a) what is the vertical component of this velocity? b) what is the horizontal compenent of this velocity?

Malcolm

water

how many degrees of freedom does water have

Trescka

What can you do on mars?

What can you do on mars?

Qadeer

What does radiation mean?

What does radiation mean?

Omara

what initial action is the reason behind beginning a scientific investigation?

what initial action is the reason behind beginning a scientific investigation?

Robb

what is big bang theory

Explain in detail about big bang theory

Tatania

What is friction?

What is friction?

Jo-Anne

what is Kinetic and potential energy

I'm taking GCSE Sciences as separate subjects and really struggle with physics can anyone help me with the above question please?

Ayisha

what is the connection between current and voltage??

what is the connection between current and voltage??

Wylie

What is the difference between longlitudinal waves and transverse waves

also what does it mean when a wave is polarised ?

Savak

What is the lifecycle of a star and how does it happen?

What is the lifecycle of a star and how does it happen?

Lynn-Anne

what is the missing word: the greater the mass, the something the pull of gravity

what is the missing word: the greater the mass, the something the pull of gravity

Safaira

what is the significance of the time it takes for a communications satellite to orbit the earth

what is the significance of the time it takes for a communications satellite to orbit the earth

Jackaleen

What to research when doing an ISA?

I'm doing an ISA in Physics at school but I don't know what to research! please help me?

Maaike

Who uses the hubble space telescope?

Who uses the hubble space telescope?

Cari-Anne

Why does a compass point North?

Why does a compass point North & would it also point North on the Moon if there is a North on the Moon?

Kenan

Why does a magnet behave like a magnet?

I understand the concept of electricity well but I'm not able to understand what is exactly going on inside a magnet. I don't understand what creates the magnetic effect of a magnet. How can electricity be generated from magnet and magnet be generated from electricity? What is really going on in terms of atoms and charges and everything?

Allyson

why when the sun is taken in x ray it appears green

http://www.open.edu/o.../content-section-1.1 Figure 8 please need help fast thanks

Bronwyn

Work and Power

A 100N girl rides a 50N bicycle a total of 150m at a constant speed. The frictional force against the forward motion of the bicycle equals 25N. How much work does the girl do? Explain your answer.

Siobhain

Would i need to know about FlipFlop Logic Gates for GCSE

Would i need to know about FlipFlop Logic Gates for GCSE

Zaynab

Why is physics important in medicine?


Why is Physics Necessary in Medicine?

Ever wonder why physics is important in the field of medicine? Well, there are numerous reasons why it is very vital to this field. In fact, this is a deceptively simple question because Physics is present in everything, from the workings of accurate medical scales, to the imaging equipment like X-rays, MRI, ultrasound….. this is why it is actually pretty hard to give a simple answer because there is so much of Physics in Medicine it’s hard to know where to start! A simple answer is that physics is useful across many aspects of medicine both in treatment but especially in diagnostic medicine, such as X-Rays, CT, Ultrasound etc. One reason why a knowledge of physics is important for medicine is “medical physics”, Medical physics is a branch of applied physics concerning the application of physics to medicine. It generally concerns physics as applied to medical imaging and radiotherapy.  Medical imaging refers to the techniques and processes used to create images of the human body (or parts thereof) for clinical purposes (medical procedures seeking to reveal, diagnose or examine disease) or medical science (including the study of normal anatomy and function. Under this are the following: An MRI scan diagnostic radiology, including x-rays, fluoroscopy, mammography, Dual-energy X-ray absorptiometry, angiography, and Computed tomography ultrasound. One of the most important factors you ought to consider is the fact that the study of modern medicine is complemented with technology. Your knowledge of Physics can be useful to understand the underlying science behind these technologies, what makes them work and the applications. You see physics is a great help in the field of medicine without it, we are not able to enjoy what we are enjoying today in terms of treating our diseases.

Brandon

Mechanical Waves vs Electromagnetic Waves: What are the Differences?

There are many types of wave and although they all have things in common there are also behaviours and characteristics that can distinguish them from each other. For example, we could look at the direction of travel of the wave in relation to the movement of the particles of the medium they are travelling through which would allow us to categorise waves into 3 categories such as transverse waves, longitudinal waves, and surface waves. Or we could look at the waves ability or inability to transmit energy through a vacuum? This leads us to 2 notable categories of waves, mechanical and electromagnetic.

Mechanical vs Electromagnetic Waves

  • Electromagnetic waves can travel through a vacuum, that is an empty space, whereas mechanical waves cannot. They need a medium to travel such as water or air. Ripples in a pond are an example of mechanical waves whereas electromagnetic waves include light and radio signals, which can travel through the vacuum of space.
  • Mechanical waves can be classed as elastic waves because their transmission depends on the medium's (water, air etc.) elastic properties.
  • Electromagnetic waves are caused because of the varying magnetic and electric fields. They are produced by the vibration of the charged particles.
  • Because of these differences, the speed of each type of wave varies significantly. Electromagnetic waves travel at the speed of light but mechanical waves are far slower.
  • Electromagnetic waves are called a disturbance, and mechanical waves are known as a periodic disturbance.

Mariana

What means gravity?

  What means gravity?

Jada

Can we book an appointment for tomorrow at 5.30.

There was no conclusion and the end of the experiment, all we had to do was the experiment, write up the results, produce a graph and then there was a written paper that was part of the ISA, I will prepare myself better for tomorrow. However, next weeks ISA is on Emulsions in which I will be asked to do an experiment etc then there will be a written paper. I thought the written paper would be about Emulsions however I can't seem to link theory and practice!

My

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