Height Definition and 1000 Threads

  1. Pushies

    CoM reduced by total body height when bending your knee X degrees

    Lets say that a man with a standing height of 185cm bent his knee 30 degrees, how many centimeters will be reduced from his standing height? Assume his femur length is 60cm and his tibia (shin) length is 50cm. Can anyone give me a hint? I've tried to use trigonometry but i don't think i fully...
  2. S

    Calculate pump height by using the Bernoulli Equation

    Really need to help getting started with this one. They've given NPSH = (Ps - Pvp)/qg Where Ps = Suction pressure at pump inlet Pvp = vapour pressure of liquid at temp of pumping q = density of liquid g = acc due to grav They've also provided Darcys friction Equation The examiners tip (its a...
  3. K

    B Energy changes that result when something drops from a height

    Energy is always conserved, when something drops to the ground, potential energy changes to kinetic energy and as soon as it hits the ground it changes to another form of energy. If it's an elastic collision, from what I have learnt, the kinetic energy on colliding with the ground will be...
  4. P

    Finding the height of a focus point via ray tracing @ Snell's Law

    So far all I can work out is that the angle of incidence of the outer two and inner two rays is zero degrees, however, I can't work out how to get started on the problem. I feel like I need to use vertical slowness rather than the normal snell's law since I'm working with a dZ rather than a dX...
  5. T

    How to calculate jump height from the force and a person's weight

    If you want to see the video just search dwight howard sport science
  6. L

    MHB Jack and Jane: Same Height, Different Growth

    Suppose Jack and Jane are the same height, and Jack's height increases by 15% to 5.75 ft. If Jane does not grow, what is her height?Thank you in advance for your help and time.
  7. E

    How does the rotation of Earth affect the height of a tidal bulge?

    I'm having some conceptual difficulty with this; here's what (little!) I've done so far. Suppose the distance between the centres of the Earth and the moon is ##x## and that the radius of the Earth is ##r##, and let the gravitational field strength due to the moon at the near side, far side and...
  8. S

    Conical Pendulum: Solving the Height Issue

    So in this instance height is longer than the 3m string which is impossible. Do we just say that when ever H>L, H=L?
  9. currently

    Partial Derivative of a formula based on the height of a cylinder

    The function should use (r,z,t) variables The domain is (0,H) Since U is not dependent on angle, then theta can be ignored in the expression for Laplacian in cylindrical coordinates(?)
  10. G

    Find the height to which a mass rises

    Hi, Could I please ask for help regarding the following question. The book answer H = ( 3 - 3 sqrt(2)/4 ) L (natural length of string is L) Here is my diagram: The green level represents the unstretched string. The blue level is the string and mass in equilibrium. The purple level is the...
  11. F

    Upper bound height and lower bound height of a 3-ary ordered tree

    how to find upper bound height and lower bound height of 3-ary ordered tree that have leaves of 101? ( the tree don't have to be complete tree, but have to be have 3 children) $$m^h \ge 101=3^h \ge 101$$ $$log \, m^h \ge 101=3^h \ge 101$$ $$h \ge 5$$ but how to know upper bound and lower...
  12. B

    Height and Acceleration of a Satellite in Orbit

    a) Eg = Gme/r^2 r = √Gme/Eg r = √[(6.67x10^-11 N*m^2*kg^2)(5.98x10^24 kg)]/(4.5 N/kg) r = 9.41x10^6 m h = r2 - r1 h = 9.41x10^6 m - 6.38x10^6 m h = 3.03x10^6 m that's over 3000 km. Did I not use for right equation? Is Eg not 4.5 N/kg? Also for b), isn't the force of gravity the centripetal...
  13. saxman2u

    How to calculate TDH of PVC downspouts and water tank height?

    Greetings, Looking for the best way to calculate TDH for some rainwater catchment systems I am designing in Texas. Some homes we are installing these systems on have large footprints, between 6,000 to 8,000 sq feet. The large rainwater collection tanks we install range between 30,000 and...
  14. L

    Atwood System - max. height of the lighter object

    Magnitude of acceleration of system: a = (4.59kg - 1.71kg)(9.81N/kg)/(4.59kg + 1.71kg) = 4.48 m/s^2 Velocity of lighter mass when heavier one hits the ground: vf^2 = vi^2 + 2ad = 0 + 2(4.48m/s^2)(2.60m) vf = 4.83 m/s [up] I am not sure what to do from here? I don't really understand what...
  15. G

    MHB How Do You Calculate the Slant Height of a Cone?

    Hello, Could anyone help me understand the steps on the below questions? A cone has a total surface area of 300π cm² and a radius of 10 cm. What is its slant height? A cone has a slant height of 20 cm and a curved surface area of 330 cm2. What is the circumference of its base? I'd really...
  16. A

    Projectile Motion with Unknown Initial Height

    First, I tried solving for the total time of flight, which I got as 100 = 5cos25*t --> t=22 s Since we know the height at which the object lands, but not at which it is launched, I tried setting up the equation as: yf = 40 - y0 = y0 + 5sin25*(22) - 1/2(9.8)(22)^2 However, I got y0 = 1183 m...
  17. Adesh

    Derivation of the change of air pressure with height

    If we take a slab of air with cross-sectional area of A and height dz in our atmosphere. Now, what we do is make an argument like this :- Pressure from below must balance both the weight and Pressure from above to keep the slab at rest. ( I have added an attachment for clarification) And...
  18. P

    Force on Dam: Height or Amount of Water?

    Just had this pondering: Does the force on a water dam depend merely on the height of the water column behind it or does it depend on the total amount of water behind it? For the same dam if I have a lake behind it that is just a few metres wide vs. having a vastly large lake behind it with the...
  19. Physics345

    Question regarding the differential height of mercury in a manometer

    Given: ##y_{2} - y_{1}= 0.2m## ##Q= 1.5\frac{m^{3}}{min}## ##Q= 0.025\frac{m^{3}}{s}## After conversion ##D_{1}= 0.2m## After conversion ##D_{2}= 0.1m## After conversion ##r_{1}= 0.1m## ##r_{2}= 0.05m## ##p_{1} - p_{2} = \frac{1}{2}P(v_{2}^{2}-v_{1}^{2}) + Pg(y_{2}-y_{1})## Calculating...
  20. Z

    MHB The height of a section of overlapping circles.

    Say I have two identical circles, both of radii of one, overlapping, as shown in the diagram below: In this diagram, x is the circumference of the circles, and the bit of the bottom circle which is drawn blue (the overlapping bit) is 1/6th of the whole circumference. What I'm looking for is...
  21. J

    I I'm confused about the effect of gravity anomalies on sea height

    Summary: Lower than average weight at the equator causes the Earth to be wider, yet positive gravity anomalies are claimed to cause an increase in sea height. Summary: Lower than average weight at the equator causes the Earth to be wider, yet positive gravity anomalies are claimed to cause an...
  22. WrathofAtlantis

    Could wing height position (through changing pitch) affect propeller airflow?

    I am talking about low wing single engine WWII fighter types. In particular, I am interested in accelerated propeller airflow through the transition/curvature of the prop slipstream spiral distribution around the wing, from being partly below, towards mainly above the wing. This as the wing's...
  23. harrypoterfan

    Solving for image height given ##h_o, d_i##, and r

    $$f = -\frac{-30}{2} = 15$$ solving for ##d_0## in $$f^{-1} = d_i^{-1} + d_0^{-1}$$, $$d_0 = (f^{-1} - d_i^{-1})^{-1}$$ = -36.1364 solving for ##h_i## in $$m = \frac{h_i}{h_0} =-\frac{d_i}{d_o}$$, $$h_i = -d_i\times\frac{h_0}{d_o} = 0.4987$$ I'm told by webassign that it should be negative...
  24. T

    MHB Finding Chord length given arc length and arc height?

    I am in the process of making a tent and need to get two curved surfaces to meet. I need to find the length of a Chord of a circle given that I have the Arc length and Arc Height (that's all), no radius or anything else. I suspect that I will need a radius to find this. Or am I missing a...
  25. WhiteWolf98

    Fluid Mechanics: Flow rate required to achieve a constant height

    Some thoughts that I've had on the question are saying the volume flow rate (##Q##) in, must equal the volume flow rate out. If that's the case, then: ##Q_{in} = Q_{out}## ##A_1V_1=A_2V_2## But... no areas have been given. And height doesn't enter this equation at all. Then I thought it...
  26. J

    How to find the max height a projectile can reach on a hillside

    Here's a fully typed version of the problem with a diagramMy attempt: Given the angle of the hill, I know that the horizontal displacement of the arrow and my vertical height on the hill are related by ##Δx=d+\frac h {Tan(60)}## ...(1) where d is the distance of the enemy from the base of...
  27. Emilyyyyyyyyy

    Calculate the impact force when falling from a height

    To find vx vx = dx/t = 3.86 m/1.5 s= 2.573 m/s To find Ek Ek = ½mvx²= ½(79.4)(2.573)²= 262.8 J W = FnetΔd Fnet = 262.8 J/ 3.86 m = 68 N He hits him with a force of 68N
  28. T

    Maximum height for water from a fire hose

    Homework Statement Fire hose has diameter of 4.0 cm and flow rate of 10 L/s. There is pressure of 2.2 bar inside the hose. How high the water can go at best? Water density is 1.00E3 kg/m^3 and air pressure outside the hose is 1.0 bar. Homework Equations Flow rate $$ Q = Av $$ Newtons...
  29. N

    Find an expression for the height of this frustum

    Homework Statement A frustum is made by removing a small cone from a large cone. The cones are mathematically similar. (please see picture attached) The large cone has base radius r cm and height hcm. Given that volume of frustum/volume of large cone = 98/125 Find an expression, in terms of...
  30. A

    B Why is the height of a liquid not affected by the radius of a U-Shaped tube

    Why the height of liquid is not affected by the radius of U-Shaped tube . ..my textbook says this and it does make sense because if increase the radius of u shaped tube the height of liquid should decrease as the liquids take shape of their container. Edit : I could not make the title longer...
  31. Lapse

    Need to find final Height, Equation not Working

    Homework Statement Homework Equations The kinematic equations--namely, Sf = S0 + V0Δt The Attempt at a Solution [/B] I am a bit confused as it seems this problem is very straight-forward. My known variables: X0 = 0m Y0 = 1.7m Δt = 3.92s V0 = 29m/s Θ = 60ο Yf = ? So, I just use the above...
  32. Z

    Exploring the Maths/Physics/Chemistry of a N2O Cylinder's Height

    Hello, I am trying to understand the maths/physics/chemistry behind this situation. Here is the scenario. I have 8 grams of pressurized N2O in a cylinder at 60 bar/ 900 psi. If the temperature stays constant (let's say 50-70°C, or at a temperature where the N2O can stay as pressurized as...
  33. Matt Raj

    Where Does the Ball Become Airborne?

    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...
  34. astroscout

    I Calculating STEVE's Height from Two Photos 370km Apart

    A friend of mine was able to photograph STEVE and later found out that another photographer also captured the same event. One captured it from the south and the other from the north. He has asked me if using the the information from both locations, can the height of STEVE be calculated? The two...
  35. E

    MHB Find the height and base of a trapezium

    To start with problem #5 i cut the shape Into 2, a triangle and a square, i know that the additional leg length to the triangle can be found by subtracting base 1 and base 2=4 so i have a triangle with a hypotenuse of 8 inches, 1 leg=4 and now i have to find the length of the other leg. The...
  36. E

    MHB Find the distance between points C and D if the height of the tree is 4m

    So the question is...From point C on the ground level, the angle of elevation to the top of a tree is 30 degrees. From point D, which is closer to the tree, the angle of elevation is measured to be 45 degrees. Find the distance between points C and D if the height of the tree is 4m. I know...
  37. D

    Lawn/Garden Increase the Height of Water Spouts in Garden Ponds

    Hi all, I am new to this forum and seeking help with a project that I am working on at the condominium complex where I live in Thailand during the winter months. We currently have 3 ponds with water spouts in each pond. At this time the water nozzles spray (bubble up) to about 12-14 inches. My...
  38. P

    Swinging Tarzan: Solving for Maximum Height & Angle

    Homework Statement Tarzan runs at 6 m/s and grabs a vertical vine (negligible mass) of length 4.1 m which is tied to a branch at the top. Tarzan then swings up. Determine the maximum height Tarzan will swing up and the maximum angle the vine will make with respect to vertical. Homework...
  39. Raihan amin

    Equilibrium height of an air parcel

    Homework Statement An air parcel is investigated to study the weather.It rises up and rests at an equilibrium height in the atmosphere,where its weight is exactly balanced by the upward buoyant force. We shall assume ideal gas law to hold for all processes and neglect the mass of the air...
  40. J

    Moving Down a Ramp: Answers & Explanations

    Homework Statement Please look at the problem attached as a screenshot. Homework Equations Assuming frictionless, Ei = Ef, which means objects that are the same will end up in the same heights (so we can group A&C, B&D, and E&F). For A&C and E&F, mgh = KE_rot + KE_trans For B&D, it is mgh...
  41. O

    Determining the height an arrow reaches when shot from a bow

    Hi, I'm trying to attempt the "Try it yourself" on the bottom-right corner of the image attached, but I am struggling. As you see in the other image I attached, in one scenario I took into account the kinetic friction (which did not lead me anywhere since I needed to know the velocity of the...
  42. bbbl67

    Helicopter height and vertical speed?

    Homework Statement This is not my homework question, I was asked to help with it, but I've been out of the engineering field for many years now. Here's the question: Starting from rest, a 2500 kg helicopter accelerates straight up at a constant 1.7 m/s2. What is the helicopter's height at the...
  43. A

    Finding Momentum when giving the mass and height

    A 50.0-kg male dancer leaps 0.32 m high. (a) With what momentum does he reach the ground? I know that to find momentum the equation is P = mv, but I only have the mass and distance. I have tried finding the time (D = 1/2at^2) and later used that time to find the velocity (v = d/t). I later used...
  44. J

    Variation of potential energy with height

    Homework Statement Show that the variation of gravity with height can be accounted for approximately by the following potential function V = mgz(1+z/re) in which re is the radius of the Earth. find the force given by the above potential function. Homework Equations V = GM/r The Attempt at a...
  45. L

    Kinematics: find maximum height

    Homework Statement A rocket takes off from the launch pad and moves directly upward with an acceleration of 29.4 m/s2. It runs out of fuel after 4s and continues to coast upward, reaching a maximum height before falling back down to Earth. a) Find the rocket's maximum height. b) What is the...
  46. DracoMalfoy

    Projectile Motion Kinematics: Finding maximum height

    Homework Statement A ball is kicked with an initial speed of 20m/s at an angle of 50° above the horizontal. What maximum height does the ball reach? Homework Equations Vfx=VicosΘ Δx=VicosΘt Vfy=(VisinΘ)+ay⋅t (Vfy)^2=(VisinΘ)^2+2ay⋅Δy Δy=1/2(Vfy+(VisinΘ))⋅t The Attempt at a Solution I...
  47. K

    The height of a dielectric material between two coaxial pipes

    Homework Statement This is the exercise 10.6 from Feynman lectures on Physics 2. Two coaxial pipes of radii a and b(a<b) are lowered vertically into an oil bath. If a voltage V is applied between the pipes, show that the oil rises a height H. Show that H=(V^2)(κ-1)ε_0/[ln(b/a)ρ(b^2-a^2)g] where...
  48. ISamson

    Finding height and area of trapezoid from its legs and bases

    Hello. I am wondering how I can find the area of a trapezoid from its two legs and bases. My problem: ABCD is a trapezium with AB parallel to CD such that AB = 5, BC = 3, CD = 10 and AD = 4. What is the area of ABCD? If we trace a straight line from A down parallel to the height of the...
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