Physics homework Definition and 292 Threads

Homework Statement I have a problem where a guy runs 28.5m in 11.5s, waits 45s, then runs back to the starting point in 22s. What's the average velocity? Homework EquationsThe Attempt at a Solution Would it be zero because the displacement is zero or would I calculate the 57 total meters ran...

Homework Statement There is a tether ball swinging around in a uniform circle on a rope that is 1.90m long. Marcus hit the ball so hard that the string holding the ball made a 20.0 degree angle to the horizontal. What is the tension in the rope if the ball has a mass of 1.40 kg? Assume that the...

Homework Statement A) Suppose you are on Earth's equator and observe a satellite passing directly overhead and moving from west to east in the sky. Exactly 12.0 hours later, you again observe this satellite to be directly overhead. How far above the Earth's surface is the satellite's orbit...

How many stones (mass=2kg) are needed to lift a TV (mass=12kg) on a seesaw? What is the weight of the stones? TV? Net force? I DEEPLY apologize if I posted this question in the wrong section AND if this question seems idiotic and simple. I am a student in high school and I am not experienced...

Homework Statement A student holds a book at rest on the palm of her hand. She lifts the book straight up, bringing it to rest again at a higher point. 1. Is the net work done on the book positive, negative, or zero? 2. Is the change in the gravitational potential energy positive, negative...

Homework Statement An unknown hydrocarbon ion required 9.415*10^-6 seconds to travel through the 0.250 T magnetic field of a mass spectrometer with a radius of curvature of 14.1 cm. Since the magnetic chamber is shaped like a 'D' it only travels half way around the circle. a. find the speed...

Homework Statement An m1 = 7.6 kg block and an m2 = 10.7 kg block, connected by a rope that passes over a frictionless peg, slide on frictionless incline. Find acceleration of boxes and tension of the rope. Homework Equations F=ma I'm not sure what else The Attempt at a Solution I'm really...

Homework Statement A vertical spring is 10.0 cm long when supporting a 20.0 kg mass, and it is 12.0 cm long when supporting a 32.0 kg mass. Assume the stretch is linear with the load. a) What is the length of the spring with zero load? (0.06666667) b) How much work would be done in...

1. Homework Statement The system is in equilibrium. All the surfaces in the image are rough. The direction of friction on B due to A is : (a) is upward (b) is downward (c) is zero (d) depends on the masses of A and B. ANS : (a) Homework Equations MAg = 2μN (Friction due to wall and due to B)...

[FONT=Arial]Can someone check these for accuracy please? 1. Homework Statement 1. Light really passes through the position of a real image whether or not a screen, film, or ground glass is there to catch it. 2. You need a screen or ground glass to make a virtual image visible. 3. In a...

Homework Statement A student is rolling a baseball off the roof of their house into their backyard pool.The house is 20 feet tall, and they roll the baseball off the flat roof at speed of 3 m/s towards the pool. How long is the ball in the air and how far away is the distance the pool must be...

Homework Statement Sheldon moves a box of comic books to stuarts comic book store by attaching a rope to the box and pulling with a force of 90 N at an angle of 30. The box of comic books has a mass of 20 kg and the coefficient of kinetic friction between the bottom of the box and the sidewalk...

Homework Statement A ball is held by a vertical tether C. The vertical tether C is held be tethers A and B (which are slanted). Tether A has an angle of 30 degrees. Tether B has an angle of 60 degrees. The ball has 150 Newtons. The system is in an equilibrium. What are the Newtons in theaters...

Hello everyone, I have this physics assignment to do and I would sure appreciate your guy's input. My attempts to answer the questions are below. Could you please let me know if I'm correct or if I'm wrong or missing anything? Thanks a lot in advance! 1. When you drive a car, might you...

Homework Statement I've gotten to the point where I have ln(e^(-cx) - e^(-cy)) = ln(g) how do i solve this for x ?

Physics homework problem -- design a capacitor Homework Statement An engineer needs to design a capacitor with a capacitance of 1*10-6F using a material with a dielectric constant 260. If the dielectric strength of the material is 8*106 N/C, and the maximum voltage that the capacitor is...

The conductive tissues of the upper leg can be modeled as a 35-cm-long, 16-cm-diameter cylinder of muscle and fat. The resistivities of muscle and fat are 13 Ωm and 25 Ωm, respectively. One person's upper leg is 82% muscle, 18% fat. The resistivity of the whole leg will be a weighted average of...

Homework Statement PLEASE click on attached picture below: What can be concluded about the tension in the cords holding the balls stationary in Systems I and II when both systems are at rest? In both systems the mass of the larger ball M2 is exactly twice the mass of the smaller ball...

Which equation is valid only when the angular measure is expressed in radians? A. α = Δω/Δt B. ω= ΔΘ C. ω^2 = ωø^2 + 2αθ D. ω = Vt/r E. θ=1/2αT+ωøT

Homework Statement Typical household currents are on the order of a few amperes. If a 1.60A current flows through the leads of an electrical appliance, how many coulombs pass through it in 6.50min ? Homework Equations I=ΔQ/Δt The Attempt at a Solution 6.50min=1min/60s= 0.108s...

Can you check my physics homework please?? Homework Statement My physics project includes predicting (1) the time it takes a ball to go down a slide http://i.imgur.com/TfQI87H.png I'm not sure if it's right though. (2) finding the coefficient of friction between me and the slide...

Homework Statement A 15.0 g bullet with a speed of v = 235 m/s is fired into a block of wood that is initially at rest on a frictionless surface. The block of wood is attached to a horizontal massless spring with a spring constant k = 195 N/m that is initially uncompressed. The other end...

Homework Statement An unmarked police car traveling a constant 80km/h is passed by a speeder traveling 135km/h. Precisely 3.00s after the speeder passes, the police officer steps on the accelerator; if the police car's acceleration is 1.50m/s2 , how much time passes before the police car...

Homework Statement In deriving the formula div v = \frac{∂v_{x}}{∂x} + \frac{∂v_{y}}{∂y} + \frac{∂v_{z}}{∂z} we used a rectangular solid infinitesimal volume; however, any shape will do (although the calculation gets harder). To see an example, derive the same formula using the prism-shaped...

Homework Statement The homework my professor gave me is... We have a tank filled with a liquid, it has a hole at the bottom of the tank. The tank does not taper. the hole is at the bottom and not on the side. No extra pressure is applied to the liquid to help it drain and the top of the...

1. So for today's exam, I was given this equation, and I was required to get the value and units of K: T4 = (4K∏4)/g2 - (8d∏4)/g2 I had to follow an experiment, plot the results, get the gradient. After getting the value of g, I was required to find the value of K, and its units. T4 has...

Physics Homework Help -- Force when kicking a ball Homework Statement I have a few physics problems on my homework, I need help. A player kicks a 0.5kg ball with a force of 50N, what is the force on his foot? Homework Equations F = Mass * Acceleration The Attempt at a Solution...

Homework Statement A large barge filled with scrap iron is in a canal lock. If the iron is thrown overboard, does the water level at the side of the lock, rise, fall, or remain unchanged? Homework Equations None. I like math a lot but this class I'm taking is a prerequisite to...

Homework Statement Bronco Brown wants to put Ft =∆mv to the test and try bungee jumping. Bronco leaps from a high cliff and experiences free fall for 3 seconds. Then the bungee cord begins to stretch, reducing his speed to zero in 2 seconds. Fortunately, the cord stretches to its maximum...

So I told my sister I could help her with her physics homework, having an old computer engineering degree, and this first problem she sends me has me stumped. If anyone is willing to help this busy and forgetful young man help his sister I would be immensely appreciative. Thank you in advance...

Homework Statement --F-->{3.9kg}{5.8kg}{8.3kg} Three blocks are in contact with each other on a frictionless horizontal surface. A 413 N horizontal force is applied to the block with mass of 3.9 kg as shown in the figure below. The acceleration of gravity is 9.8 m/s2 . d)What...

Homework Statement A 2,254-kg car is moving down a road with a slope of 10 degrees while speeding up at a rate of 1.1 m/s^2. What is the direction and magnitude of the frictional force? (define positive in the forward direction, i.e., down the slope)? Homework Equations ax=μgcos-gsin...

Homework Statement The first problem I am having trouble with is as follows: A child pushes a 40kg sled across the ice at a constant speed. If μk = 0.05 calculate the force applied to the sled. Homework Equations I know that f=\muFN The Attempt at a Solution I know that the...

I've tried several problems similar to these where I could get the answer checked without locking me out of my homework attempts, but I'm not really understanding what to do at all here - any and all help would be appreciated. An airplane flies 200 km due west from city A to city B and...

Homework Statement Ts (subscript s) = 2∏*√(4.5*10^-2 kg / 2.0*10^3 kg/s^2) kg = Kilograms s = seconds Ts = ? Homework Equations I do not have any relevant questions. The Attempt at a Solution Ts = 2∏*√(4.5*10^-2 kg)/√(2.0*10^3 kg/s^2) Simplified Ts = 6.28*[(0.212 kg)/√(44.72...

Hi, have a physics test coming up on Tuesday, and I was wondering if you all would like to help me out with a couple questions! 1) A highway is to be built between two towns, one of which lies 70.0 km south and 72.0 km west of the other. (a) What is the shortest length of highway that...

Homework Statement ??Homework Equations ?? The Attempt at a Solution I'm not even sure where to begin with this problem...

tried posting in homework help, but haven't received a response would appreciate any input! original topic: https://www.physicsforums.com/showthread.php?t=584077 the problem: http://desmond.imageshack.us/Himg839/scaled.php?server=839&filename=truss1.png&res=medium i can't figure out...

Homework Statement The engine of Sara's 1290 kg car exerts a force of 4880 N at the wheels. She accelerates for 8.73 seconds and then unfortunately, she collides with a snowbank. A) find the force that would stop her car in 2.32 seconds from the impulse of the collision. B) Calculate her...

Homework Statement A golfer finds that when he is at the driving range, he can send the ball a maximum distance of 250m before it strikes the level ground. Once on the golf course, the golfer finds that in order to get a hole in one, he must hit the ball so that is lands a distance of 200m...

George Washington Gale Ferris. Jr., a civil engineering graduate from RPI, built the original Ferris wheel. The wheel carried 36 wooden cars, each holding up to 60 passengers, around a circle 76m in diameter. The cars were loaded 6 at a time, and once all 36 cars were full, the wheel made a...

Homework Statement [If a ball of mass (400g) falls from a height of (1.5m) towards the ground, and rebounds a height of (1m), find: a) Initial Potential Energy b) Kinetic Energy of ball before hitting the ground c) Velocity at which it reaches the ground d) The velocity at which it...

Physics Homework Help! Please! I have homework due ASAP! Please help, I'm clueless on where to even start ! 1. A sample of neon gas has its volume tripled and its temperature held constant. What will be the new pressure relative to the initial pressure? 2. A fire breaks out and...

I'm a physics teacher. Do you know of any available physics problem books or sources (free or otherwise) for: * intro level, lite-algebra high school applied physics course * standard high school algebra-based physics course (AP Physics B) * standard high school calc-based physics course...

Homework Statement During a test crash, an air bag inflates to stop a dummy's forward motion. The dummy's mass is 75 kg. If the net force on the dummy is 825 N toward the rear of the car, what is the dummy's deceleration? Homework Equations w=mg The Attempt at a Solution...

Hi, I have a general question about physics homework after the first year. It is a mix of bewilderment and apprehension. I'm doing very well in my first semester of calc-based physics, and I knock off the problem sets in a few hours. But I hear that the first year is relatively mild, and...

Having trouble with my physics homework, if anyone could please help me with how to this, that would be awesome. My teacher says we are supposed to find the X and Y componenets and then add them, but I don't know how to find them. The Smith's go on vacation. They travel 16.0 km north/west...

I need help on this question for my postlab, thanks ! By direct substitution, show that equation (3) is a solution of the differential equation (2) α(t)=α0 cos(√(g/l) t) (3) (d^2 α)/(dt^2 )=-g/l α (2) α = angle alpha in degrees α0 = amplitude of motion g =...

Hi, this is my first time using this forum, so i have no idea if this is even the correct place to be asking for help. I have a problem with my High School Higher Physics Homework. The question is as follow : Homework Statement During one run, a car and passengers of mass 800kg are released...

Homework Statement Here is the picture: I have an upcoming test, and I cannot seem to get any questions like this one. Help is greatly appreciated. I calculated the net force, such that Fnet=ma. There exists a magnetic force due to the current in the wire. The mass m is negligible, ie...