Physics homework Definition and 298 Threads

A 2.0 kg mass slides down a frictionless inclined plane that makes an angle of 30 degrees with the horizontal. The sass starts from rest. What is its speed after it has slid a distance of 3.0 m along the incline? I got: F = (sin30)(9.8) F = 4.9 N W = Fd W = (4.9) (3) = 14.7 J W =...

Pepe, the clown, is jumping on a trampoline as Babette, the tightrope walker, above him suddenly loses her balance and falls off the tightrope straight toward Pepe. Pepe has just started upward at 15.0 m/s when Babette begins to fall. Pepe catches her in midair after 10.0s. a) How far has...

I think someone may have previously asked for help on a problem similar to this one: There are three blocks connected by a string. m1 is 0.5kg, m2 is 1.7kg. m1, and m2 are connected at the top of a surface and m3=2.9kg, is hanging of the end of a pulley. looks kinda like this: [ m1 ]----[...

I've been having some problems with these problems, I'd appreciate any help. 1. There are 2 people standing on a roof 80 m high, person #1 throws a ball straight up in the air with an initial velocity of 20 m/s, person #2 has a replica of the ball and drops it off the roof at the same...

New to physics, and I'm a little confused on one problem on my homework: 1) A runner runs 5.0km along the course east, then turns around and runs 5.0km west along the same path. She returns to the starting point in 40 min. What is her average speed and velocity? The speed was easy to...

i need help with this problem. I've tried for a while now and it is driving me crazy! I've tried about everything including using what little calculus i remember from last year! please help! the problem is: you are standing on a cliff and you drop a rock straight down, neglecting air resistance...

i am confused on how to set up a problem involving initial and final momentum . . . please help

let V = R^{4}. Consider the following subspaces: U = { (a,b,c,d) in R^{4} : a + 2b + 3c = 0, a + b + c + d = 0 } W = { (a,b,c,d) in R^{4} : a + d = 0, b + c = 0 } find a basis for U and a basis for W. i don't even know where to begin. Any help would be very much appreciated. Thanks.

1. A car is parked on a cliff overlooking the ocean on an incline that makes an angle of 21 degrees below the horizontal. The driver leaves the car in neutral and it rolls from rest down the incline with a constant acceleration of 3.37 m/sE2 for a distance of 70.0 m to the edge of the cliff...

Hello people, pardon my poor grammar and my horrible spelling. Let my make it clear to all that in not looking for someone to do my homework. I just need a push on the right direction. :mad: -------------------------------------------------------------------------- a ball with the mass of...

This is my 3rd practice question that I don't know how to do :( Hoping peole can help me out, if someone could even work it out, would be greatly appriciated. A skydiver, weighing 70kg, jumps from an aeroplane at an altitude of 700 metres and falls for T1 seconds before pulling the rip...

I have two homework problems i need help with one is: 1) A 4kg load is hanging on the bottom of a vertically positioned spring that stretches 10 cm down. Find K of the sping. 2) There are three blocks connected by a string. m1 is 10 kg, m2 is 20kg. m1, and m2 are connected at the top of a...

Two friends, Al and Jo, have a combined mass of 168 kg. At an ice skating rink they stand close together on skates, at rest and facing each other, with a compressed spring between them. The spring is kept from pushing them apart because they are holding each other. When they release their arms...

OK ... i figured out the momentum, however i need help with find the mass. anyone know how? What is the momentum of a 0.33 nm X-ray photon? 2.009E-24 kg · m/s What is its effective mass? _________ kg thanks :biggrin: :biggrin:

HI, I'm new in this forum. I really need help with my physics homework. Would you guys please help me with this question: " Explain,in terms of the properties of electromagnetic waves, what causes 'ghosting' of a TV picture?" What i can say at the moment is that 'ghosting' of a TV picture...

Physics Homework Help Needed: Optics--Lens Here's the physics problem that I need help: A converging and diverging lens are placed 5.0 cm apart, and an object O is placed 5.0 cm from the first lens. Each lens has a 5.0 focal length. What happens to the image position if the lenses are...

A car heading north collides at an intersection with a truck heading east. If they lock togethr and travel at 28 m/s at 38° north of east just after the collision, how fast was the car initially traveling? Assume that the vehicles have the same mass. Does this problem not depend on how fast...

Physics Homework Problem--Stuck? A 75 kg water skier is being pulled by a horizontal force of 495 N and has an acceleration of 2.0 m/s2. Assuming that the total resistive force exerted on the skier by the water and the wind is constant, what force is needed to pull the skier at a constant...

I have two questions from a worksheet that i am having problems over. It is over Newton's laws. They are: A late traveler rushes to catach a plane, pulling a suitcase with a force directed 30.0 degress above the horizontal. If the horizontal component of the force on the suitcase is 60.6 N...

Okay...so I have Physics homework due at midnight, 8 hours. And I'm stuck on a few problems...posting here for some help. An explanation of how to do it would be much more appreciated then just answer. 1a)A 1816 g mass is on a horizontal surface with μk = 0.48, and is in contact with a...

A car drives straight off the edge of a cliff that is 51 m high. The police at the scene of the accident note that the point of impact is 134 m from the base of the cliff. How fast was the car traveling when it went over the cliff? I don't know where to begin with this problem. Can someone...

Physics Homework Problem--Stuck! A diver springs upward with an initial speed of 1.7 m/s from a 3.0 m board. a. Find the velocity with which he strikes the water. (Hint: When the diver reaches the water, his displacement is y = -3.0 m (measured from the board), assuming that the downward...

A diver springs upward with an initial speed of 1.7 m/s from a 3.0 m board. a. Find the velocity with which he strikes the water. (Hint: When the diver reaches the water, his displacement is y = -3.0 m (measured from the board), assuming that the downward direction is chosen as the negative...

a force of 40 N accerlerates a 5 kg block at 6 m/s^2 along a horizontal surface.. a) how large is the frictoinal force? b) what is the coefficient of friction? For Ans A, how would i find frictional force... 40N-5x6 = 10 N?? thanks

physics homework need help! hi, I'm a student in eleventh grade. I'm actually working on a test for tomorrow, that, to be honest, I'm really not ready for. It's just regular, 1st year phyiscs. ok, well, my first question I need help with is as follows. When a punter kicks a football, is...

I just started physics about a week ago. We got this problem for extra credit, and I need help with it. A rock is dropped off of a cliff and the sound of splashing water is heard 3.4 seconds later. The speed of sound is 340 m/s. How high is the cliff? Any insight/help you could give me...

A man standing by a rail track, hears the whistle of a train at a frequency of 10419.7 Hertz. The train is moving towards the man at a speed of 39.9 meters/sec. The frequency of the whistle (in Hertz) is Student response 9207.612 Correct answer 9164.147 frequency heard by the man =...

Homework problem... Please can you help me with this problem. I don't understand what its asking and I don't know where to begin : It says : A car travels at a speed of 50mph from point A to B. The distance traveled is 1200 km. How long does the journey take ? Thanks guys for any...

I was wondering if I could post some problems from my physics homework that I did so that it can be checked by you guys. So is it okay?

The front and rear sprockets on a bicycle have radii of 9.00 and 5.10 cm, respectively. The angular speed of the front sprocket is 8.60 rad/s. (a) Determine the linear speed (in cm/s) of the chain as it moves between the sprockets. cm/s (b) Determine the centripetal acceleration (in...

Two billiard balls of equal mass move at right angles and meet at the origin of an xy coordinate system. One is moving upward along the y-axis at 3 m/s, and the other is moving to the right along the x-axis with speed 4 m/s. After the collision (assumed elastic), the second ball is moving along...

Hi fellow physicists, I have some homework problems I'm trying to work through and i need to know if I'm on the right track. This is the problem: A Spring is upright (vertical) and has a constant k and a length Lo, a tray of M mass is attached to the spring and on the tray is placed a...

Hello, I was wondering if anyone could help me with the following question: How long does it take for a shoe to drop 75 m from rest? What is the final velocity? I have that the acceleration is equal to gravity at -9.8 m/s squared and that the distance is 75 m and the intial velocity is...

I'm having some problems with this question, A ball is thrown directly downward, with an initial speed of 8.25 m/s, from a height of 29.4 m. After what time interval does the ball strike the ground? I tried 29.4 + 8.25 m/s(x) + 1/2(-9.8m/s)(x), but that didn't turn out to be right. Can I get...

One afternoon, a couple walks five-eights of the way around a circular lake, the radius of which is 1.35km. They start at the west side of the lake and head due south to begin with. a) What is the distance they travel? b) What are the magnitude and direction (relative to due east) of...

Emergency Landing. A plane leaves the airport in Galisto and flies a distance 155 km at an angle 68.0 Degrees east of north and then changes direction to fly a distance 270 km at an angle 48.0 degrees south of east, after which it makes an immediate emergency landing in a pasture. 1.) When...

This is really giving me trouble. The problem is on the following site: http://home.earthlink.net/~suburban-xrisis/index.mht OKay, what I thought of was mgh=.5mv^2 so therefore g(5r/2)=.5v^2 I'm not sure how to connect it all to a=v^2/r any ideas?

Need some help here quick, needs to be turned in in the morning...How do we find the magnitude of the magnetic force from a straight wire with a 12 amp current flowing thru it at a distance of .11 meters? Any help here would be greatly appreciated...Thanks

Hey y'all! My friend told me about this special forum site in which you can get help with your homework and I think that's a really useful tool. Anyways, I am currently enrolled in Physics 30 and I need some help. So instead of posting a new thread everyday, this is the name I gave to my...

I need help on what formulas to use and how to start this physics problem. We estimate that there are 260 million plug-in electric clocks in the United States, approximately one clock for each person. The clocks convert energy at the average rate of 3.6W. To supply this energy, how many...

I have a HW problem for non-calculus based physics that I can't seem to figure out. Please help me if you can: Consider a sphere of radius R woth a uniform positive charge distribution (rho)=q/V. Using Gauss's law, prove (a) that the magnitude of the electric field outside the spherical...

Help Please! Hello Could someone help me with this problem? thanks Part A: A container holds 35.0 kg of water at 20.0 C. HOw much energy must be removed from the water to turn it completely into ice at 0 C? Part B: The block of ice is projected a cross a surface at an initial speed...

can anyone help me with this question from my homework? i have the system in the picture and i need to find out the type of movement of the bar. the box named A is an inductor, the 2 long parallel lines are infinite conductors. there's a magnetic field into the page. the black bolded line is a...

Determine V1 and R3 if R1= 8ohms I1= 0.75A, R2=5 Ohms and I2=6A. Note that R2 and R3 are connected in parallel. Thank you.

Hey all-- Can someone try to ifnd what I'm doing wrong with this question, I must have sort of brain lapse in the middle of a 4-day weekend and all: Question: A (very large) door has a mass of 44,000kg, and a rotational inertia about a vertical axis through its hingesof 8.7*10^4 kg*m^2...

We were given a WebAssign for homework dealing with forces. I got most of the problems, but there were a few I didn't understand at all. If anyone could help me, it would be much appreciated. 1. The helicopter in the drawing is moving horizontally to the right at a constant velocity. The...

hi, i am doing my physics homework at the moment, and i have got stuck on the last part of a question. it is asking for the resistivity of the wire- the values i have are length of wire 2.5m, cross sectional area 2.0mm squared, current of 3.0a flowing through driven by p.d. of 4.5V. the first...

Hi, I'm new to this forum, I'm taking honors Physics this year and I'm not sure of what I'm doing in this homework problem... "Joe pushes on the handle of a 10 kg lawn spreader. The handle makes a 45 degree angle with the horizontal. Joe wishes to accelerate the spreader from rest to 1.39...