# physics please HELP !

128,227 results, page 30

### Physics

A cricket ball rotates at 1800 rev/min as it travels through the space in a straight line at 160 km/hr. How many times does it revolve after traveling 20m? Can someone confirm with me if 13.5 revolutions in 20m is right. That's the answer i got too. If it's wrong can someone ...

### physics

PLEASE HELP! When Babe Ruth hit a homer over the 10 m -high right-field fence 80 m from home plate, roughly what was the minimum speed of the ball when it left the bat? Assume the ball was hit 1.2 m above the ground and its path initially made a 39 ∘ angle with the ground.

### Physics

Ive tried numerous methods, but I cant seem to get this right. Please help, and explain step by step. An object's position is given by x=bt+ct^3, where b=1.50m/s and c=0.640m/s3. To study the limiting process leading to the instantaneous velocity, calculate the object's ...

### Physics (Please Help)

At the He-Ne laser wavelength (L= 632.8 nm) the refractive indices of crystal quartz are n o = 1.54264 and n e = 1.55171 calculated from its Sellmeier equation. The laser is incident from the air onto the surface of crystal quartz at an angle of incidence of 45 degrees. For ...

### physics PLEASE HELP

A source emits sound uniformly in all directions. There are no reflections of the sound. At a distance r1 from the source the sound is 6.5 dB louder than it is at a distance r2 from the source. What is the ratio r1/r2?

### physics

a +35x10^-6 C point charge is placed 32 cm from an identical +32x10^-6 C charge. how much work would be required to move a +50.0x10^-6 C test charge from a point midway between them to a point 12 cm closer to either of the charges? please show work.

### Physics

True/False 1)Specular reflection obeys the laws of reflection while diffuse reflection does not. False. drwls said its true but I disagree can you please explain. 2)A convex lens is used to obtain an enlarged virtual image. True.

### PHYSICS

Could u help with physics hw! i keep trying but i keep getting the wrong answer? a 71g autographed baseball slides off of a 1.3 m high table and strikes the floor a horizontal distance of .83m away from the table. 1.how fast was it rolling on the table before it fell off? ok ...

### math

On the first day he runs 1.5 km. Every day he runs 10% more than the day befor. a) Write down the distance he runs on the second day of training. ..... 1,5km +0,15 = 1,65 km b) Calculate the total distance He runs in the first seven days of training. When I counted my answer ...

### Physics Help!!!! Please check

A 3.00 kHz tone is being produced by a speaker with a diameter of 0.150 m. The air temperature changes from 0 to 29°C. Assuming air to be an ideal gas, find the change in the diffraction angle . Please tell me where I am going wrong. first I converted the temp to kelvin 0 = ...

### Physics

One of the most powerful cranes in the world, operating in Switzerland, can slowly raise a load of 6000 tonne to a height of 12 m. (1 tonne = 1000 kg) The acceleration of gravity is 9.81 m/s2 . How much work is done by the crane? Answer in units of MJ I found it by using Work...

### Physics

Could someone please explain how you get this answer??? A skier with a mass of 60.0 kg pushes off with a horizontal speed of 3.0 m/s from the top of a snow covered hill. As he slides down the hill, his height decreases by 42 m over a distance of 100 m of travel. How much will ...

### Physics

Calculate the change in momentum in each of the following situations and state the direction of the change in momentum. a) A 4kg bowling ball strikes a stationary pin head-on at a speed of 3m/s. It continues to move in its original direction, but its speed is reduced to 2m/s. ...

### Physics

Calculate the change in momentum in each of the following situations and state the direction of the change in momentum. a) A 4kg bowling ball strikes a stationary pin head-on at a speed of 3m/s. It continues to move in its original direction, but its speed is reduced to 2m/s. ...

### Physics

I agree with this and see were it comes from net force = (delta p)/t so momentum is conserved when net force equals zero... net force = (delta p)/t 0 = (delta p)/t however the following is not true 0 = (delta p)/t = P - Po were p is momentum and Po is used to indicate inital ...

### PHYSICS

A mass is thrown upwards with an initial velocity of 30m/s. A second mass is dropped from directly above, a height of 60m from the first mass 0.50s later. When do the masses meet and how hight is the point where they meet? I NEED TO KNOW HOW TO SHOW THIS IN A STEP BY STEP ...

### Physics

The frequency of circular motion for a charged particle moving around in the presence of a uniform magnetic field does not depend on ... a)The radius of the circle b)The mass of the particle c) The charge of the particle d) The magnitude of the magnetic field e) Actually, it ...

### PHYSICS- please help! i cant get my last problem

The compound eyes of bees and other insects are highly sensitive to light in the ultraviolet portion of the spectrum, specifically light with wavelengths between 300.0 nm and 400.0 nm. To what frequencies do these wavelengths correspond? (Assume that the speed of light to be 3...

### Physics

A shopper in a supermarket pushes a cart with a force of 35 N directed at an angle of 52(angle sign here) downward from the horizontal. Find the work done by the shopper on the cart as the shopper moves along a 50.0 m length of aisle. Someone tell me if this is right: W= (35....

### Physics-Please help with formula

If you were in a rotor style ride and the riders accelerate until the speed of ride is reached- if the radius of the cylinder is 5.0m and the coefficient of friction between clothes and wall is 0.5, how do you find minimum speed you would need to stick to the wall of the ride...

### physics

two ends of a train moving with constant acceleration pass a certain point with velocities u and v. what is the velocity with which the middle point of the train passes the same point? I have asked this question before you have answered u+v/2. but my mam says it is (u^2+v^2/2...

### Physics

For the first part of this question I got 12.12m/s B. With the help of a friend the boy measures the height to which the ball returns and finds it to be 5.2 meters. How fast was the ball moving when it left the ground? I wrote this down mass of ball: 0.40kg height if house: 7....

### physics

Two pieces of metal (A and B) are identical in every way, except that A has a much larger thermal expansion coefficient. If equal amounts of heat are added to both pieces of metal, which metal does more work on its surroundings? 1. A 2. B 3. They do the same work. 4. Unable to...

### physics

A bicyclist wants to make it from one building to the next. The first building he is standing on is 20 m tall. The building he wants to reach is 12 m tall. He is moving at 4 m/s and the gap between both buildings is 5 m. Will he make it? Please just show me how to break down ...

### physics please help

a 65 kg bag is dragged along a 12m ramp in order to get from the ground to the floor of the loading dock 2m above the ground. determine the efficiency of of the ramp. The frictional force acting on the bag is 50N due to the ramp. I don't understand how to the find the energy ...

### Math/physics

This is my last problem. Please help! A motorcycle rider starts out on top of a ramp 10 m high and then rides down and jumps the motorcycle when he comes to the end of the ramp (like evil knivel). The rider is at the peak of his jump at 5 m. How fast is the motorcycle going ...

### Physics

We have a heat engine that produces 150 J of heat, does 40 J of work, and emits 110 J into another system. What is the efficiency of the heat engine? Please don't give me the answer! Just help figure out how to find it! The description for the lesson with this question was 1 ...

### English

Posted by rfvv on Thursday, December 16, 2010 at 3:40pm. Posted by rfvv on Thursday, December 16, 2010 at 3:21am. {At a restaursant} For hear or to go? Is this for here or to go? It's for here, please. It is to go, please. (Are the expressions above all grammatical? What is ...

### Physics(Please check)

A rectangular plate is rotating with a constant angular speed about an axis that passes perpendicularly through one corner, as the drawing shows. The centripetal acceleration measured at corner A is n times as great as that measured at corner B. What is the ratio L1/L2 of the ...

### physics urgent please help!

way safety engineers build soft barriers so that cars hitting them will slow down at a safe rate. A person wearing a safety belt can withstand an acceleration of 300 m/s 2 . How thick should barriers be to safely stop a car that hits the barriers at 81.7 km/h? Answer in units ...

### math help

Thank you for helping me with the last problem Reiny and Bosnian. However, I have one more problem that I need help with please and I have no idea how work the problem. I used an on line calculator to get the answer. It didn't give an explanation on how to do the problem ...

### physics

Suppose the amount of heat removed when 3.0kg of water freezes at 0 degree C were removed from ethyl alcohol and its freezing/melting point of -114 degree C. How many kilograms of ethyl alcohol would freeze? PLEASE GIVE ME SOME HINTS!!!THANKS A LOT!!!!

### physics

4.8mF capacitor in series with 500 ohm resistor is connected, via a switch, to a 12V battery. What is the current through the resistor at t=1.0s after the switch is closed? I tried doing I^2R = 1/2 CV^2 and solving for I but the answer wasn't correct. can some1 please help? ...

### physics help

An auto race is held on a circular track. A car completes one lap in a time of 16.9 s, with an average tangential speed of 48.1 m/s. Find the following (a) the average angular speed (b) the radius of the track i found part a which was .3716 but need help with part b please

### physics help

The earth orbits the sun once a year (3.16 10^7 s) in a nearly circular orbit radius 1.50 10^11 m. With respect to the sun, determine the following. (a) the angular speed of the earth 1 rad/s (b) the tangential speed of the earth 2 m/s (c) the magnitude and direction of the ...

### Physics 1

At t = 0, a stone is dropped from a cliff above a lake; 1.3 seconds later another stone is thrown downward from the same point with an initial speed of 33 m/s. Both stones hit the water at the same instant. Find the height of the cliff. No idea how to get the height. Help please!

### Physics

A boy throws a ball straight up into the air so that it leaves his hand at 11 m/s. 1) If the ball has mass 0.15 kg and the boy's arm moved through 1.5 m as he threw the ball, then what average force did he exert on the ball? Please show it step by step along with the equation ...

### Physics

A boy throws a ball straight up into the air so that it leaves his hand at 11 m/s. 1) If the ball has mass 0.15 kg and the boy's arm moved through 1.5 m as he threw the ball, then what average force did he exert on the ball? Please show it step by step along with the equation ...

### Physics

Starting from rest, a 5kg block slides 2.5 m down a rough 30o incline in 2 seconds. Find a) the work done by the force of gravity. b) the work done by friction. c) the work done by the normal force Help ASAP please!! Show work step by step only with the equation

### physics

sorry! trying to get the drawing correct! PLEASE HELP!! I HAVE A TEST TOMORROW!! i just posted this problem but a very important drawing was left out! if Q=30 uC, q=5.0 uC, and d=30cm, what is the magnitude of the electrostatic force on q in N? (Ke= 8.99 x 10^9 Nm^2/C^2) (uC= ...

### Physics please help!!

A man with mass m =96.4 kg (weight = 212.1 lbs is walking towards a patio at 2.00 m/s (4.47 mph) when, at the last moment, he realizes the sliding glass door is closed. He puts out his hand suddenly to stop himself, and comes to a halt in 90.0ms. Find the magnitude of the ...

### Physics

A string is wrapped around a pulley of radius .20m and momentum of inertia .40 kg•m^2. The string is pulled with a force of 28 N. what is the magnitude of the resulting angular acceleration? Can someone please go through the steps or at least guide me through them. I missed ...

### Physics

A string is wrapped around a pulley of radius .20m and momentum of inertia .40 kg•m^2. The string is pulled with a force of 28 N. what is the magnitude of the resulting angular acceleration? Can someone please go through the steps or at least guide me through them. I missed ...

### can someone please help w/ physics?

An object of mass 154 kg moves in a smooth straight tunnel of length 2990 km dug through a chord of a planet of mass 3.19 × 10^24 kg and radius 1 × 10^7 m Find the eﬀective force constant of the harmonic motion. The value of the universal gravitational constant is 6....

### Physics

Please Help I have no idea how to approach this problem In a "Rotor-ride" at a carnival, people rotate in a vertical cylindrically walled "room." If the room radius was 5.7m , and the rotation frequency 0.35 revolutions per second when the floor drops out, what minimum ...

### Physics

I understand that I have to use newtons laws of motion but I don't really get how to aplly them to this problem. Please help. An aircraft with a mass of 11000kg moving at constant speed and altitude is powered by propellers and experiences drag from air. The thrust is 225kN ...

### physics again (check answers please)

What net force increases a velocity of a car from 20 m/s to 35 m/s in 8.0 s if the mass of the car is 1600 kg? (3000 N). What force would cause the car to stop? (3000N) What coefficient of friction is needed to supply the force of friction? (.0191) are they correct?

### physics urgent please asnwer it i m begging u

a metal sample carrying a current along X-axis with density Jx is subjected to a magnetis field Bz(along z-axis). the electric field Ey developed along Y-axis is directly proportional to Jx as well as Bz. the constant of propotionality has SI unit. 1. m²/As 2. m²/A 3.As/m³ ...

### Physics

A concave spherical mirror has a radius of curvature 15 cm. A 1 cm tall bulb is placed in front of the mirror such that its image is formed 10 cm in front of the mirror what is the focal length position of object magnification of object height of object Please help!! I am ...

### physics

if the coeffiecient of friction between a 32kg metal plate and the floor is 0.16, what force is required to roll this metal plate across the floor at a uniform speed? how much work is done if the metal plate is rolled to a distance of 15m? Please response i need your help.

### Physics

A 2.00-kg object is hanging on a 1.1m string. The object is pulled 20cm away from the equilibrium position and held there. a) What is the pulling force in the string when the object is kept still ? b) Now the object is released, what is the speed of the object when it goes ...

### AP Physics

A certain length of wire has a resistance of 21 ohms. This wire is melted down and from the same volume of material a new wire is formed that is three times longer than the original wire. What is the resistance of a new wire? ***PLEASE SHOW ALL WORK!!!

### Math

PLEASE PLEASE HELP ME WITH THESE 2 PROBLEMS STEP BY STEP AND SHOW WORK! z/12=9 what is the value of z show how you found it. 5 x g= 230 what is the value of g show how you found it. PLEASE I REALLY NEED HELP!!!

### PHYSICS PLEASE HELP QUICK

An object with an initial speed of 4.0 meters per second accelerates uniformly at 2.0 meters per second2 in the direction of its motion for a distance of 5.0 meters. What is the final speed of the object? Vi=4m/s a=2.0m/s*s d=5.0m Vf=? Vf©÷=Vi©÷+2ad Vf©÷=(4m/s)©÷+ 2(2m...

### physics

i REALLY don't get this problem. PLEASE HELP!!! the position of a runner during a 3 second time interval the runners position changes from x1 = 50m to x2 = 30.5m what was the runners average velocity? find the average speed as well as the average velocity.

### PHYSICS PLEASE HELP

A satellite has a mass of 5850 kg and is in a circular orbit 4.50 x 10^5 m above the surface of a planet. The period of the orbit is two hours. The radius of the planet is 4.20 x 10^6 m. What is the true weight of the satellite when it is at rest on the planet's surface?

### Physics

A block of aluminum that has dimensions 2.07 cm by 2.55 cm by 5.00 cm is suspended from a spring scale. The density of aluminum is 2702 kg/m^3. (a) What is the weight of the block? 0.699 N (b) What is the scale reading when the block is submerged in oil with a density of 817 ...

### Physics

A heater cansupply 98000J an hour. If a lot of ice is already at 0 degrees, how much ice can be turned to water? check my work please: Q/l=m 98000J/kg / 3.35 * 10^5J = 029kg of ice can be turned to water

### Physics - Rube Goldberg Project

I need to make a Rube Goldberg Machine and it must demonstrate projectile motion, conservation of energy and conservation momentum, any idea on what to make and how to make it? Help please

### Physics-Help Please!

a 25gram bullet is fired upward through a .36kg block. the block goes up 17cm in the air and the bullet goes up 24m into the air. What is the initial velocity of the bullet?

### Physics Please

A boy on a swing is pulled to a position 2.34 m off the ground and released. At the fastest and lowest point of the swing the boy is 0.50 m off the ground and travelling 3 m/s. The percent efficiency of this swing system is?

### Physics

Calculate amount of energy needed to completely vaporize a 50g piece of 20 degree C silver melting point 1064 C L(f) = 64KJ/Kg Boiling point 2856C L(v) = 1645 KJ/Kg c= 0.13KJ/Kg degrees C I'm thinking I balance each side to equal each other but I'm not dure-I've done specific ...

### reading

sentense with 11 elephant Please keep in mind that we don't do students' homework for them. Once you write a sentence, please re-post and someone here will let you know if you're right or need to work on it some more. =)

### pre-cal/trig

PlEASE help me with this!! I need it as soon as possible....... cos(x-(pi/4))+sin(x-(pi/4))=1 Find the answer from 0 to 2pi. When I slove this, I got cosx+sinx=(1/ square root of 2). then I don't know what to do the rest. Please help me.

### Ms. Sue please

Could you please clarify what your intentions were behind what you said on Friday the 24th in a thread that was marked as "society"? The time stamp was 2:22. I have already left my own personal interpretation there.

### PLEASE AND THANK U

i just want to sat that I appreciate all u teachers helping me, but please don't provide one site for me which is Wikipedia. I don't understand a single thing wen I reach that page. It confuses me more, but thanx

### calculus please help

I posted this below but had no response. I would appreciate help with details please.How do I find the indefinite integral of h(u)=sin^2(1/5u) this is one fifth u. Does it involve double angle formulas? Thanks.

### calculus--please helpp

if the line 3x-4y=0 is tangent in the first quadrant to the curve y=x^3+k, find k. all i know is that its related to finding a derivative and i m basically completely lost....can please someone provide me some help?????

### pre-calc HELP PLEASE

solve using identities for all angles (dont use multiple angle method)show work please cuz i am so confused. 2sin2x-3sinx=0

### matt/116

Will someone please help me find the answer to this question please. How do you write a system of linear equations in two variables? Explain this in words and by using mathematical notation in an equation.

### social studies

3 things in history that impacted in south America,europe,asia,africa and austrlia.(please list all and I can do the rest) P.S please get back to me by tomorrow before 2 o' clock

### Language Arts

Please help me with the following: Myths often function as a connection to __________, or the customs and beliefs of a group of people. I think the answer is phenomena, but I don't even know if that is correct. Please help me, any help will be appreciated.

### math algebra

COULD SOME OF WITH DEGREE IN MATHS HELP ME TO SOLVE THIS SIMULTANEOUS EQUATION PLEASE, PLEASE ? I HAVE RIED DIFFERENT METHODS BUT IT CANNOT GET THE CORRECT ANSWER, AS IN THE BOOK. X-3/4 -Y-2/5 = -1/4 (1) 4-X/3+ 3-Y/2 = - 13/20 (2) 5x-15-4y+8= -1 5x-4y=17-1 8-2x+9-3y= -13 -2x-...

### English

Two students talked about the title. Now, one last student....OK. Well done. Please remain quiet, everyone. ------------------- Would you check the short passage? Correct any errors, please.

### Social studies please help soon I'm timed please

Which religion considers the epic poem about Krishna one of the most important texts? A: Buddhism B:Hinduism C: judaism D: Zoroastrianism

### Pre calc

Please help me proof the identity. This isn't even math to me, I can not understand it so please show all work. God bless A)1-cos2x/sin2x=tanx B) sin4x/sinx=4cosxcos2x

### graphic design please help

i tried to find the answer but i come up with nothing please help any links or any thing will be helpful In 1-2 paragraphs describe the importance of prioritizing your focus when designing for multiple purposes

### physics

A ball of moist clay falls to the ground from a height of 19.8 m. It is in contact with the ground for 19.0 ms before coming to rest. What is the average acceleration of the clay during the time it is in contact with the ground? (Treat the ball as a particle.) PLEASE HELP! :)

### Physics (Please help!!!)

1) An ideal gas occupies a volume of 0.60 m^3 at 5atm and 400K. What volume does it occupy at 4.0atm and a temp of 200K? I know how to find the volume with the m^3 and the atm but it threw me off since it gives the 4.0 atm and the temp 200K.

### physics. please help!

A 2.5 kg block is pulled to the right by a horizontal string. The coefficient of static friction between the block and the floor is 0.30 and the coefficient of kinetic friction is 0.20. What value of force applied by the string will start the block moving?

### Physics

A sample of serum has a mass of 54 gm and a volume of 225cm. What's the density in g/cm? I think the answer is .24g/c please correct me of I'm wrong but my ? is what would be the mass of 150 fluid ounces of this serum? What would be the volume of 1 pound of this serum?

### Physics PLEASE HELP

A 50-kg crate is pulled across the ice with a rope. A force of 100 N is applied at an angle of 38° with the horizontal. Neglecting friction, calculate the acceleration of the crate AND the upward force the ice exerts on the crate as it is pulled.

### Physics Please

A tennis player places a 51 kg ball machine on a frictionless surface, as shown below. The machine fires a 0.067 kg tennis ball horizontally with a velocity of 33.4 m/s toward the north. What is the final velocity of the machine?

### Physics

11. An object with a charge of +6.0 µC is 0.30 m from a second object and experiences an attractive force of 1.80 N. What is the magnitude of the charge on the second object? (µC = 1.0 × 10-6 C) (Answer: -3.0 µC) Can someone please explain how to do this problem? I don't ...

### physics. urgent answer please

Two forces 10 N acting in the direction N 30 east and 15 N acting in the eastern direction, if both forces act at a point, find the magnitude and direction of (a) the resultant force (b) the equilibriant force.

### Physics

A liter of water is used to cool some electronics. If 1000 J of heat is given off by the electronics, by what temperature does the water increase? One liter of water has a mass of 1 kg and a specific heat of 4.184 J/(g °C). I can not get this..please help

### College

Does Harvard University have art & creative writing classes cause I want to become a artist & a creative writer (when writing books, short stories, novels, & poems). I'm just asking. I look on the website but it really confusd me. Please also what is REALLY Harvard Uninersity...

### PHYSICS

The masses and coordinates of four particles are as follows: 40 g, x = -4.0 cm, y = 5.0 cm; 30 g, x = 5, y = 0.0 cm; 40 g, x = –5.0 cm, y = 3.0 cm; 20 g, x = 3.0 cm, y = 2.0 cm. What are the rotational inertias of this collection about the (a) x, (b) y, and (c) z axes? >&...

### physics-repost

An owl has good night vision because its eyes can detect a light intensity as small as 5.0*10^-13W/M^2. What is the minimum number of photons per second that an owl eye can detect if its pupil has a diameter of 8.5nn and the light has a wavelength of 510nm? Can anyone please ...

### Physics - Important

a car attempts to stop and slides 25.5m while accelerating at -4m/s^2. The car's initial velocity was 20m/s. Find the time the slide took. Note that the final velocity is not known and that you need a quadratic solution. I know the quadratic formula, but I'm not sure how to ...

### physics

in an emergency stop to avoid an accident, a shoulder-strap seat belt holds a 60kg passengr firmly in place. if the car was initially travelling at 90km/h and came to a stop in 4.5s along a straight, level road, what was the average force applied to the passenger by the seat ...

### Physics-Please check

If I had the old-fashion camera that had a focal length of 35mm(0.035m) and I take a picture of a person 6 m away, how far does the film need to be from the lens to record a clear image? I know that the equation is 1/f = 1/d(object) + 1/d(image) so would I do the following: 1/...

### Physics; help please :)

Two wires made of the same material of density 7240 kg/m3 and having the radius in the ratio 1:2 but the same length 1.54 connected together and stretched by a force of 540 N. If the speed of a transverse wave through the thinner wire is 3600 m/s, calculate the wave velocity ...

### AP Physics

An electric furnace runs nine hours a day to heat a house in January (31 days). The heating element has a resistance of 10.6 ohms and is hooked up to a 240 Volt potential. What does it cost to run the furnace in the month of January if the cost of electricity is $0.15 per KW*...

### Physics help please

excited by the in class experiments you put two speakers in your living room 80cm apart producing a sound of 750Hz. 4.0 m away you place a microphone right on the centerline between the speakers. Will the microphone detect a loud sound or a soft on at this point (relatively to...

### physics

HELP PLEASE!!! A satellite moves in a circular orbit around Earth at a speed of 5085 m/s. (a) Determine the satellite's altitude above the surface of Earth. (b) Determine the period of the satellite's orbit.

### English Survey(please post)

what book do you think should be made into a movie? and why?(please state reason clearly.) consider the questions below: what's the benefit if it was made into a film? is there something that you think can be presented in the movie better than the book? why do you think people...

### Math

How do you work this problem step by step? p-12 when p= 22 We don't know what book you are using and probably none of us has a copy if you told us the name of the book. Please post your question and someone will try to help. Please be specific and tell us exactly what you don'...

### physics help please!

The motion of a piston in an auto engine is simple harmonic. The piston travels back and forth over a distance of 23 cm, and the piston has a mass of 1.7 kg. 2515 rpm 23 cm max speed of the piston 30.28757 m/s What is the maximum force acting on the piston when the engine is ...