Hill Definition and 317 Threads

Homework Statement My attempt at a solution was to say: Eki = Ekf + Eg and my Ek 's all has 1/2 on them... other than that, my solution is essentially the same thing. I end up with sqrt( vi2 - sg(delta)h ) = vf What's up with this?

Homework Statement A solid uniform marble is rolling without slipping when it approaches the base of a hill with a speed v0. Find the maximum height above the base that this marble will reach if the hill is rough enough to prevent slipping. Homework Equations Since there is no...

Homework Statement A girl coasts down a hill on a sled, reaching level ground at the bottom with a speed of 6.2 m/s. The coefficient of kinetic friction between the sled’s runners and the hard, icy snow is 0.059, and the girl and sled together weigh 736 N.The acceleration of gravity is 9.81...

Homework Statement A car of mass 1100kg starts from rest at sea level and climbs a hill of altitude of 50 m. At the top of the hill the car has a speed of 25 m/s. The work produced by the engine of the car is? Homework Equations W= F(d) F= ma The Attempt at a Solution W =...

Homework Statement Johnny jumps off a swing, lands sitting down on a grassy 20 degree slope, and slides 3.5m down the slope before stopping. The coefficient of kinetic friction between grass and the seat of Johnny's pants is 0.5 Homework Equations F=ma Frictional force = \muN...

Hello! Just wondering if anyone could point me in the correct direction with these problems? Homework Statement "A skier coasts down a very smooth, 10 m high slope. If the speed of the skier on the top of the slope is 5.0 m/s, what is his speed at the bottom of the slope?" and... "If...

Homework Statement A child runs down a 13 hill and then suddenly jumps upward at a 17 angle above horizontal and lands 1.5 down the hill as measured along the hill. What was the child's initial speed? Homework Equations Unknown. Been trying to use trig to solve distances and as a...

Homework Statement Jack and Jill ran up the hill at 3.6 m/s. The horizontal component of Jill's velocity vector was 2.3 m/s. (a) What was the angle of the hill? (b) What was the vertical component of Jill's velocity? Homework Equations ? The Attempt at a Solution I don't...

I'm bypassing the normal questions, only because I have already solved the question, but want help figuring out why the answer is what it is (without incorporating numbers into it at all). The idea is that a car is at the top of a hill going a constant speed. We are to treat the hill as having...

Homework Statement A 1-lb block and a 100-lb block are placed side by side at the top of a frictionless hill. Each is given a very light tap to begin their race to the bottom of the hill. In the absence of air resistance, what can you conclude about the outcome of the race? Homework...

Homework Statement The van travels over the hill described by y=(-1.5(1/1000)x^2 + 15)ft. If it has a constant speed of 75ft/s, determine the x and y components of the van's velocity and acceleration when x=50ft. http://img215.imageshack.us/img215/3631/dynamcs.jpg Homework EquationsThe...

At 6'5", 300 lbs. and old as dirt, I am a walking and rolling testimate to F=ma. This part of my project is difficult for me, because I have never taken a physics class. All the examples I have in books and PF, deal mostly with force moving down a hill. I am trying to compute Watts and Calories...

newbie question, say I'm rolling a ball down a smooth , differentiable, and frictionless 1-Dimensional hill V(x) from a point x_i find the location x(t) and the velocity dx/dt(t) of this ball at some arbitrary time t. what would be the general approach towards such a problem? note that for...

Homework Statement A boy drags his 60N sled at constant speed up a 15 degree hill. He does so by pulling with a 25N force on a rope attached to the sled. If the rope is inclined at 35 degrees to the horizontal What is the coefficient of kinetic friction between the sled and snow? At the...

Homework Statement A snowmobile climbs a hill at 6.526m/s. The slope of the hill is a 1 ft rise for every 40 ft of distance. The resistive force of the snow is equal to 3.3 percent of the weight of the snowmobile. How fast will the snowmobile move downhill, assuming the engine delivers the...

I have a very simple conceptual physics problem that I am looking to solve, and unfortunately I've been out of school a little too long to solve: Suppose you have a hill, and at the bottom of the hill it levels off and keeps going on. You take two marbles of different masses and roll them...

I know that the idealized problem using gears and force without considering biophysics will tell me there is basically no difference in energy between riding a bike up a hill in low or high gear. I have often wondered which actually uses more calories. Many people tend to go to a lower gear...

How do i solve this? here's how far I've gotten suppose i have x[q], y[q]=S, the surface of a hill dy/dx=(dy/dt)/(dx/dt) atan(dy/dx)= the angle of incline at a location on the hill -GM*cos(pi/2-atan(dy/dx))=the tangeantal component of acceleration im ignoring the perpendicular...

Homework Statement Calculate the acceleration of the train during the trip down the first hill Time for train to go from top of hill to bottom:3.5 s Time for train to pass point at top of hill 1.5s Time for train to go from bottom to top of first hill:7 s Time for train to pass point of...

Homework Statement A sports car is accelerating up a hill that rises 16.0° above the horizontal. The coefficient of static friction between the wheels and the road is µs = 0.87. It is the static frictional force that propels the car forward. (a) What is the magnitude of the maximum...

A skier weighing 0.80 kN comes down a frictionless ski run that is circular (R = 30 m) at the bottom, as shown. If her speed is 12 m/s at point A, what is her speed at the bottom of the hill (point B)? http://www.physics.gatech.edu/people/faculty/larry/images/16212.gif I keep getting...

A Mercedes-Benz 300SL (m = 1700 kg) is parked on a road that rises 20° above the horizontal. (a) What is the magnitude of the normal force? (b) What is the static frictional force that the ground exerts on the tires? Homework Equations FN=Wcos(theta) Wsin(theta)=Framp (at least that's...

A box 80.0N is to be pulled across a smooth horizontal floor with a force of 20.0N at an angle of 60 degrees to the horizontal. What acceleration will be produced? I know this probably seems simple, but I have searched my lecture notes, my textbook and the web but I can't find out how to...

I have been accepted into UNC and am anticipating an acceptance letter from State. I had planned on attending State because I wasn't sure if I would get into UNC, but now that I have I can't decide where I won't to go. So my question is which school has the better math department? I plan on...

Hi there currently I am stuck on a question, A car with a mass of 1.2 tonnes, rolls down a hill which is 600m long and is inclined at an angle of 9 degrees to the horizontal. Ignoring the effects of air resistance and friction and assuming the car to start from rest at the top of the hill...

Homework Statement A sight seen on many "bunny" hills across Ontario is young skiers pushing on ski poles and gliding down a slope until they come to rest/ Observing from a distance, you note a young person (approximately 25 kg) pushing off with the ski poles to give herself an initial...

A ball rolls at an initial velocity of 4.00 m/s up a hill. 5 seconds later it is rolling down the hill at 6.0 m/s. <---- What does the question mean? Did the ball roll up for 5 seconds and then started rolling down? Find its acceleration Find its displacement at 5.0s

Homework Statement A toy car with mass m=15.0g rolls without friction along a track that goes over a hill. The hill is in the shape of an arc of radius R=35.0cm. The center-of-mass (CM) of toy car is 0.5cm beyond the point of contact with the track. At the instant shown in the drawing its...

Homework Statement A car is driven at constant speed over a circular hill and then into a circular valley with the same radius. At the top of the hill the normal force on the driver from the car seat is 0. The driver's mass is 70.0 kg. What is the magnitude of the normal force on the driver...

Homework Statement Homework Equations KE=(0.5)mv^2 PE=mgh The Attempt at a Solution a.) The tanks volume is 20m^3. I then multiply that by the density to get the mass of the water, which is 20,000 kg. Apply that into PE=mgh for gravitational potention...

Homework Statement Jeremy is trying to walk up an icy sidewalk. If he has leather shoes (coefficient of leather on ice = 0.3) then what is the steepest angle up which he can safely walk? What would have to be his coefficient of friction if the hill were 65 degrees? Homework Equations...

Homework Statement In Figure 6-58, a stuntman drives a car (without negative lift) over the top of a hill, the cross section of which can be approximated by a circle of radius R = 211 m. What is the greatest speed at which he can drive without the car leaving the road at the top of the hill...

A child and sled with a combined mass of 53.8 kg slide down a frictionless hill that is 8.56 m high. If the sled starts from rest, what is its speed at the bottom of the hill? m/sim not sure how to calculate speed given the information. help please?

Homework Statement "Is more work required to bring a fully loaded truck up to a given speed than the same truck lightly loaded? Defend your answer" Homework Equations I put: Work = Force x distance Distance = speed x time As speed in a common factor, we take it out Work = Force x...

A 1000 kg car traveling on a road that runs straight up a hill reaches the rounded crest at 25 m/s. If the hill at that point has a radius of curvature of - in a vertical plane - 75 m, what is the net downward force acting on the car at the instant it is horizontal at the very peak? How fast...

When trying to solve a problem I arrive at the following equation of motion / Hill equation: \frac{d^{2}y}{dx^2} + \frac{4 k_0}{m w^2} cos(2x)y = 0 There exists a value x_0 such that for all x>x_0 the motion is stable. I actually don't know what is meant by this 'stability'. Can...

Homework Statement A toy car has a total mass of 50 g, and rolls on freely spinning wheels, each of which can be modeled as a uniform disk of mass 1 g, and radius 2mm. What is the acceleration, a, of this toy car when it rolls without slipping down a ramp tilted at an angle of 20 degrees to...

Homework Statement a car is exerting 3.000N of force on a hill that rises 3m for each 100m of road. what is the actual weight of the car? how much force do the brakes have to exert to keep the car from rolling down the hill. Homework Equations a2 + b2 = c2 sin theta= opp/hyp cos...

Speed at the bottom of a hill - Please help! Homework Statement Bike (mass 40kg) traveling down a hill. Speed at the top of the hill is 5.0 m/s. The hill is 10m high and 100m long. Force of friction is 20N, what is the speed at the bottom? Homework Equations The only formula I've tried...

Is there any way to prove that speeding up before a hill in a car will save you gas compared to maintaining your speed on the hill? Here is the situation: Notice, the one car maintains 10m/s throughout while the second car accelerates to 20m/s on the flat part. Both cars will have...

Homework Statement Suppose a car starts coasting from the top of a hill that is 60m high. (a)How fast will it be going at the bottom of the hill if there is no friction? (b) For the same car starting at the top of another hill and reaching the bottom, without friction, at 10 m/s, how high is...

Homework Statement A bicyclist of mass 65kg (including the bicycle) can coast down a 6 degree hill at steady speed of 6km/h because of air resistance. How much force must be applied to climb the hill at the same speed and same air resistance? The Attempt at a Solution since it is at...

Homework Statement 75 kg boy, starting from rest, slides down a 30 degrees hill htat is 70 m long. He arrives a thet bottom with a speed of 15 m/s. How much thermal energy has been shared btwn the surface of the hill and the seal of his pants Homework Equations d=(vf2-vi2)/2a KE=1/2Mv2...

Homework Statement Question Details: A rope attached to a 19.0 kg wood sled pulls the sled up a 18.0 kg snow-covered hill. A 9.0 kg wood box rides on top of the sled. If the tension in the rope steadily increases, at what value of the tension does the box slip? So far none of the...

Homework Statement A cyclist intends to cycle up a 8.00 hill whose vertical height is 115 . The pedals turn in a circle of diameter 36.0 . 1:Assuming the mass of bicycle plus person is 80.0 , calculate how much work must be done against gravity. 2: If each complete revolution of the...

Homework Statement A car encounters an inclined plane Given- Weight of car in N (6500), velocity on the flat surface (22.5 m/s), power of the engine (78000), incline of the hill (8.1 degrees) Want to find- velocity on the hill (power and restistive forces remain constant) Homework Equations...

Homework Statement A bus runs out of fuel as it approaches a hill. If the hill is 0.88 m high, how fast must the bus be traveling in order to coast just to the top of the hill? Homework Equations ? The Attempt at a Solution I'm so stuck and it's drving me crazy can someone please...

Homework Statement We are pushing a sled up a hill. Our push is horizontal. The hill is inclined at 15 degrees. The sled masses 35 kg. The coefficient of kinetic friction is .2. The hills height is 3.6 m. We push at a constant velocity. How much work do we do in pushing? Homework...

Homework Statement Take down as positive. A car is parked near a cliff overlooking the ocean on an incline that makes an angle of 10.5 degrees with the horizontal. The negligent driver leaves the car in neutral, and the emergency brakes are defective. The car rolls from rest down the incline...

A truck is towing a 1.00*10^3 kg car at a constant speed up a hill that makes an angle of 5degrees with respect to the horizontal. A rope (negligable) is attached to the truck at an angle of 10 degrees with respect to the horizontal. Neglect friction. What is the tension in the rope? I'm not...