# What is Hill: Definition and 316 Discussions

A hill is a landform that extends above the surrounding terrain. It often has a distinct summit.

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1. ### How Does Mass Cancellation Affect Acceleration on an Inclined Plane?

I've found M-k it is 0.16 how to find the acceleration? I can't solve it without the quetion telling me the mass of the kid!
2. ### Find the speed of the biker at the bottom of the hill

I used the work-energy equation to solve this problem.Only the parallel component of force acts to accelerate the biker and increases K.E., so only the parallel component and frictional force does work on the biker. therefore, Net work done on a system = change in K.E (F_I{_I} + F_F) d...
3. ### Sandy Hill Plunge: A Lifted Bronco's Free-Fall

I have a scene in a story where a full-size lifted bronco with 35” tires is sliding skewed down a steep sandy hill. The driver cranks the wheel upon seeing a ledge which fails to change the trajectory of the vehicle, now sliding on sandy gravel at about 20 MPH. The rim of the front wheel...
4. ### A box with the mass m = 25 kg is sliding up a hill

What I have already attempted is on my Ipad and I don't know how to upload it on here. With hope of help DJ
5. ### Schools Choosing a College for a Bachelor's in Physics: NC State vs. UNC Chapel Hill

I need help in deciding on a college to attend for a bachelor's in physics. I live in North Carolina, and I got accepted into the following schools: Appalachian State University Georgia Tech NC State The Ohio State University Illinois Urbana-Champaign University of Maryland College Park UNC...
6. ### Automotive Speed of a car rolling down a hill

This looks like a physics question but it's not; it's an automotive question. Suppose you had a car at the top of a gently sloped hill, a 5% grade. You start it and put it in neutral or drive and it starts to roll down. You never place your foot on the brake or the accelerator and suppose the...

9. ### Bowling Ball is rolled down a steep hill

I have no idea how and what to do.
10. E

### A polygon is rolling down a hill

An ##n##-sided regular polygon is rolling down a frictional ramp at angle ##\theta## to the horizontal. I define ##\beta := \frac{2\pi}{n}## as the angle at the top of each of the ##n## isosceles triangles that make up the polygon. Let ##\omega_{k, 1}## be the angular velocity just after the...
11. ### Deceleration of rocks sliding up a hill

i have no idea how did the answer come in conclusion...i guess that cosθ and sinθ is referring to the 2 dimensions of the acceleration ? but how? and why?
12. ### Cars Collide on a Hill, Conservation of Momentum

QUESTION: ----------- For the purposes of this problem, we will define the direction of Vehicle A's initial velocity as the positive direction: While driving on a road that is inclined at an angle of 10 degrees above the horizontal, Vehicle A and Vehicle B are in a head-on collision lasting...
13. ### Projectile question — Cannonball fired over a hill

Time of flight is t = 2v sinθ /g = v/g for θ = π/6 so time to top of flight is t = v/(2g) I then constructed a right-angle triangle with θ=π/6 and opposite side of 130m and used tangent to get the adjacent side , ie. distance from cannon to hill to be 225.17m The horizontal velocity is v cosθ...
14. ### At what angle do we have to kick a ball up the hill for n-rebounds?

I decided to try and find a solution in a green (tilted) coordinate system. I started solving this problem with thinking about 1-rebound: ##⟹y=0, α=\text{angle under which we kick a ball}##; ##y=sin\alpha v_0t-\frac{1}{2}gt^2##; because I'm trying to solve this in a tilted system, I have to...
15. ### A kid slips off the top of the hill -- find the escape angle

Hi, This is my try. Are you in agreement with this ? Thanks.
16. ### How Fast Could a Car Ascend a Straightened Mountain Road?

QUESTION: If all the curves were removed, making a straight line from top to bottom, how quickly could a car reach the top of a mountain? VARIABLES: The mountain has a slope of 6.4% The car's initial velocity is 0. The car's top speed is 203 mph, (which will also be its final velocity as it...
17. ### Find the time when the projectile runs into the hill (with air resistance)

vy=vter + (vy0 -vter) e-th/τ where tau=m/b EQ 1 Okay, for part a, I used Eq 1 I let vy=vy(th)=0 --->The reasoning is that the projectile would stop moving for a short time when it hits the incline, but I have a feeling that reasoning is faulty I let vy0=v0sinθ Then the equation became...
18. ### Smooth rolling ball rolls down hill, how far can it fly?

Figure of the problem. There are many exercises like these, and I've read the whole chapter and I got no clue where to start here. Kinetic energy from gravity is: E = mgh = 39.3m I could try change v to ωr in the K equation but it will leave me nowhere because I don't have the mass nor the...
19. ### MHB Hill Cipher Attack: Eve Can Crack Alice's Message

Suppose that we are in the situation that Alice is using a Hill cipher consisting of a $2 \times 2$ matrix $M$ to send her message, which is $100$ ‘A’s. If Eve intercepts this message and knows that plaintext contained only one letter, and she also knows anyone of the entries of the matrix $M$...
20. ### Pressure / Volume Gas relationship Pendle Hill experiment

I was reading about the Pendle Hill experiment by Henry Power and Richard Towneley showing the relationship between Volume and Pressure in gas that eventually became Boyle's Law. The higher they got the greater the volume became. My question is, was the gas measured in the barometer isolated...
21. ### Worksheet Problem about Power (average power of a car accelerating up a hill)

Homework Statement A 1130 kg car is initially at rest when it accelerates up a 21 m high hill. When it reaches the top of the hill it is traveling at 18 m/s. If it takes 6.5 s to reach the top of the hill, what was the average power of the car? Homework Equations W = Fd P = w/t The Attempt at...
22. ### Cylinder rolling down the hill

Homework Statement A solid cylinder rolls down an inclined plane because of stiction. How does angular velocity change over time? Given: ##m,R,g,\alpha,\mu## where ##\mu## is the friction coefficient Homework Equations [/B] ##J_{cm} = 1/2 m*r^2## moment of inertia m = mass of the cylinder...
23. ### How can the Tesla car go up a steep hill without a gearbox?

I thought electric cars had normal gearboxes like any other vehicle but the following does not. No gear lever. It says at 6:00 that this is because the electric motor's torque is constant no matter the rpm. Presumably it means the maximum torque available is constant for all rpm. What if this...
24. ### Object on a hemispherical hill

Homework Statement There is an object at the top of a frictionless hemispherical hill with radius R. t time t=0, it is given a small impulse so that it starts sliding down the hill. Find the height from the ground where the ball becomes airborne. Express your answer in terms of R. Homework...
25. ### What velocity does a train need to go up and down the hill

Homework Statement There is a train of length d and speed v. It is heading towards a hill with height h and length of each side l. What velocity requirement must be met so that the train can go up and down the hill? Homework Equations Ek=m⋅v2/2 Ep=m⋅g⋅h The Attempt at a Solution I'm basically...
26. ### Where on the hill does the projectile land?

Homework Statement A projectile is shot at a hill, the base of which is 320 m away. The projectile is shot at 60° above the horizontal with an initial speed of 79 m/s. The hill can be approximated by a plane sloped at 19° to the horizontal. The equation of the straight line forming the hill is...
27. ### Stopping distance of a car rolling down a hill

Hello, This is an investigation I have been studying recently, can someone help with the following... 1. Homework Statement Method: 1. Place a toy car at the top of a ramp. 2. Let it go. 3. Measure the distance it travels from the bottom of the ramp. 4. Add a 100 g mass to the car and...
28. ### Engineering A car on a hill - power of motor problem

Homework Statement A car is traveling up a slope. Given that a(t) is constant at 1m/s^2, find the expression of motor power in time. Assuming that the maximum power of the car is 215kW, for how long can the car maintain such an acceleration? Mass of car (m) = 2000 kg The hill has a constant...
29. ### Calculating the Hill sphere of the International Space Station

Homework Statement [/B] The International Space Station (ISS) has a mass of 400,000 kg and orbits 408 km above the Earth’s surface. The ISS is 109 m across. Homework Equations : [/B] R=a(semimajoraxis) cubedroot(m2/3M1)The Attempt at a Solution : [/B] ive tried multiple ways with multiple...
30. ### Energy calculations for a skier on a hill

Homework Statement A skier with a mass of 45 kg is standing at the top of a 45 m hill. · Calculate the gravitational potential energy of the skier when she is standing at the top of the hill · Calculate the kinetic energy of this skier at the bottom of the hill, where she has a...
31. ### Normal Force on Car at Top of Rounded Hill

Homework Statement a 1000kg sports car moving at 20m/s crosses the round top of a hill (radius of 100 m) . Determine the normal force on the car Homework Equations Newton’s second law F=maThe Attempt at a Solution I figured out the centripetal acceleration Ac= v^2/r = 4 m/s^2 My attempt at...
32. ### Hill Cipher- Potential Cribs for 3x3 Matrix

Homework Statement I've created code to crack a Hill Cipher (n=3). I'm unsure which cribs to try to crack a specific code. Would anyone mind posting ideas? The crib must be 9 letters in length. Homework EquationsThe Attempt at a Solution
33. E

### Calculating the Distance a Rock Travels Up a Sloped Hill

Homework Statement A rock approaches the foot of a hill with a speed of 16 m/s. The hill has a slope of 23 degrees, how far up the hill does the rock travel? Homework Equations KE = PE The Attempt at a Solution I tried mv2/2 = mgy but I know this isn't right since I don't use theta at all...
34. ### MHB What Determines the Angular Momentum of a Rolling Boulder?

Dear Every one, Here is the question. How to get started with this question? A spherical boulder of mass 90.2 kg and radius 20 cm rolls without slipping down a hill 16 m high from rest. (a) What is its angular momentum about its center when it is half way down the hill? (Enter the magnitude in...
35. A

### Finding the Formula for Speed and Distance on an Icy Hill

Homework Statement Maxine (mass m) slides down an icy slope then along a flat surface before coming to a stop. The slope has angle θ and height h. a. Derive a formula for speed at the bottom of the hill in terms of the angle of the hill θ, the height from which she starts h, and the...
36. T

### Block sliding down hill splits into two blocks

I am currently working on this problem and I am stuck as to how to approach or solve it. The problem is that a block of mass 11000kg is sliding down a slope with a height of 1000m, angle of 40 degrees and the coefficient of friction between the block and the slope is 0.1. The block splits...
37. ### Calculating the Speed of a Ball Rolling Down a Hill

So I know that given a unchanging hill, and same mass between a sphere and cube, that the cube should slide down the hill faster (assuming negligible friction). This is observed through the energy "lost" by the sphere which instead of having all of its potential energy transferred towards...
38. ### What is the deceleration of a snowboarder going up a 5.0° slope?

Homework Statement Calculate the deceleration of a snowboarder going up a 5.0° slope, assuming the coefficient of friction for waxed wood on wet snow ( = 0.1). Homework Equations F = ma W = mg Fs = (Fn) Fk = k (Fn) The Attempt at a Solution Answer key says it's 1.83 m/s2. I fiddled...
39. ### I Mean and Gaussian curvature for a Gaussian 'hill' seem wrong

I'm hoping someone can help check whether my final contour plots look plausible based on the surface. I haven't done too much differential geometry but I've needed to work with Gaussian/Mean curvature for a simple 3D gaussian surface. Here's an example: (A = 7, a=b=1/(3.5)^2) It's...
40. ### Why Does a Car Accelerate When Rolling Down a Hill?

[Mod note: Thread moved from General Discussion forum, so no homework template is shown] So - I've no idea where to write this but... I was looking at this post : https://www.physicsforums.com/threads/car-rolling-down-a-hill.302812/ And started to answer it as it was similar to some stuff...
41. ### Car on a hill - reasoning for static friction

Problem : A car of mass ##m## is parked on a slope. What does static friction ##\mu_s## have to be for the car not to slide down if the incline of the hill is ##30## degrees? ******* For this problem I have the following forces, where the hill is inclined upwards to the right: Upwards ...
42. ### Does electricty gain / lose power traveling up / down hill? [Not]

(I Live in Michigan - no power at home since yesterday, and likely not until Sunday - 4 days, because of high winds.) My software genius boss (really, he's very smart,) is trying to tell me that the reason that the power companies do not bury power lines, is because it costs money to push it...
43. ### How to calculate the gravity on a hill?

The question is about a box with no movement standing on a hill. The hill has an angle of 25 degrees. The box has a mass of 40 kg. 1. Calculte the gravity This I still get: F= M x A = 40 x 9,81 = 3,9 x 10^2 The next question tough: 2. Calculate the component Fgravity,x off the gravity...
44. ### How do i calculate the necessary force on a hill

Homework Statement A box is on a 10 degree hill what is the force i have to pull to make the box move? and what force do i need to make the box move 20 meters mass of the box: 12.000 Coefficient of friction: 0.08 speed 1 m/sHomework Equations Ffriction= μ * Fnormal F= m*a[/B]The Attempt at...
45. ### How Long Does It Take a Car to Climb a Hill with Limited Power?

Homework Statement Your 1500-kg car, moving at 7.0 m/s, approaches the bottom of a hill that is 20 m high (Figure 1) . To save gas, you use on average only 3.2kW of engine power, realizing that half of the energy delivered by the engine and half of the initial kinetic energy will be dissipated...
46. ### Speed skier travelling up a hill

Homework Statement A speed skier is traveling horizontally at a constant speed of 5.80 m/s when she approaches a snow-covered hill that has a slope of 23.0° above the horizontal. The coefficient of kinetic friction between the skis and the hill is 0.350 and the combined mass of her and her skis...
47. ### Maximize the distance of projectile on a hill

Homework Statement An athlete stands at the peak of a hill that slopes downward uniformly at angle ##\phi##. At what angle ##\theta## from the horizontal should they throw a rock so that it has the greatest range? Homework Equations SUVAT equations and trig relations The Attempt at a Solution...
48. ### How high can it coast up the hill, if you neglect friction?

Homework Statement Suppose a 180 kg motorcycle is heading toward a hill at a speed of 29 m/s. The two wheels weigh 12 kg each and are each annular rings with an inner radius of 0.280 m and an outer radius of 0.330 m. How high can it coast up the hill, if you neglect friction in m? *m = 180 kg...
49. ### Biking up a hill in different gears

Homework Statement Hi there, I am doing a project for my physics class where I am attempting to calculate the amount of force and work required to go up a 10% grade hill in a variety of different gears and I am running into a lot of issues. I have already collected my data and have calculated...
50. ### Will the car make it to the top of the hill?

Homework Statement A 1500 kg car is approaching an icy (i.e. frictionless) hill as shown below. The car then runs out of gas traveling at a speed of 10 m/s. a) Will the car make it to the top of the hill? picture is attached Homework Equations vf^2 = vi^2 + 2ax[/B]The Attempt at a Solution...