1. A

    Calculating the divergence of electric field using the definition of divergence.

    If I try to calculate the divergence of electric field created by a point charge at the origin then I shall do something like this: \mathbf{E}= \frac{1} {4\pi\epsilon_0} \frac{q}{r^2} \hat r \mathbf{\nabla} \cdot \mathbf{E} = \frac{1}{r^2} ~ \frac{\partial (r^2E_r)}{\partial r} +...
  2. C

    Help calculating power required to lift a mass

    Hello, I realize that this is a Physics 101 pop quiz problem, but it's been 45 years since I was in Physics 101 I'm trying to figure out what size of a 12VDC motor to purchase to perform the following work. I have a 40 Kg tool that I want to lift 30cm within 60 seconds. If you need the length...
  3. P

    Calculating Mechanical Energy

    Hi Everyone, I can't seem to figure this problem out. Please help! 1. The problem statement, all variables and given/known data A ball was launched upwards and vertically at a speed 3 m/second up to a height 4m. Calculate the mechanical energy of the ball if its weight is 5 Newtons...
  4. M

    I need help calculating the frictional force

    to calculate the work done by friction. I have that the kinetic coefficient is .09 and I know delta x and i know for the problem the other part of the eq is cos(180).I also know mass is 215 kg. and acceleration is .131 So it is Wf= Ff*1.77*cos180 In the worked out solutions my professor but...
  5. B

    Calculating braking distance

    So I need to calculate the braking distance Relevant factors (deceleration of 5gs for a duration of 0.35seconds) Speed = 1000km/hour With this how can I calculate the distance it will take to brake?
  6. I

    Calculating Flow Coefficient

    Hello, I need help calculating the flow coefficient through a pressure reducing valve DN20. The values I currently have are: Inlet Pressure: 5 bar Outlet Pressure: 2.75 bar Flow capacity: 322kg/hr According to this website below, the density of steam at 5bar is 2.667 kg/m3 Saturated...
  7. M

    Calculating wave height from a ball on a boat

    You are sitting on a boat looking at a ball rolling back and forth on a table as the boat rocks. The position of the ball is x(t) = asin(ωt), where a = 1.0 cm and ω = 0.2π/s. Estimate the size of the waves that are making the boat rock. (This will require you to make some assumptions, state...
  8. S

    Calculating Mixture Critical Temperature and Pressure using Equation of State?

    Hello Everyone, I am trying to calculate critical Temperature and Pressure of binary and ternary mixtures using equation of state. In particular, I am using Peng-Robinson Equation of State. I combined this with Van-der Waals critical criterion to get my result, but am way off experimental data...
  9. P

    An atom moves in a region where potential energy varies: calculating the new velocity

    Alright guys, I'm new here and to physics. I'm self-teaching physical chemistry and am starting with basic physics so I'm stuck on this: Consider an atom of mass m moving along the x direction with an initial position x1 and initial speed v1. If the atom moves for a time interval Δt in a...
  10. S

    Calculating "g - force" acting on an Human Body

    Dear friends, I want to know the total g-force acting on an Human Body while accelerating. Weight of the Human Body = 70 Kg; Initial Velocity (Vi) = 0; Final Velocity (Vf) = 22.22 m/s; Start Time (ti) = 0 sec; Final Time (tf) = 1 sec; delta V = Vf-Vi = 22.22 m/s - 0 = 22.22 m/s delta t = tf -...
  11. C

    Calculating equal flow through parallel flow pipes?

    Hello everyone, I am hoping some here might be able to help with what I am hoping is a simple problem for you all. Thank you for any help I get with this ahead of time.... I am looking to run water through a series of parallel water pipes and am looking to achieve equal flow through all...
  12. D

    Calculating the frequency of output

    I was given this question: A farm has purchased a star connected 3 ph emergency generator running at 1000 rpm which has 6 poles with a total flux per pole of 0.022Wb. If the stator has a total of 72 slots with 4 conductors in each slot, determine i. The frequency of the output I have...
  13. D

    calculating slip

    Stuck on this question with the information I have got any help would be much appreciated. Calculate the slip of a 2 pole 3 phase induction motor when the supply frequency is 50 Hz and the rotor current frequency is 2 Hz. Thanks in advance for any help
  14. G

    Calculating Uncertainy

    If I want to calculate the uncertainty in X given that X = 2/(A*B)^2, how would I do it? I know the uncertainties in A and B and want to find out the uncertainty in X. Thanks!
  15. P

    Calculating period - Mass on a spring

    Hello all, I am writing a lab report for physics and I am wondering if my calculations are valid. I am to calculate the period of a mass on a spring and then to find out how the changing of that mass affects the period. The original formula I am meant to use is 'T = n/t', the number of...
  16. D

    Calculating g with time intervals of thrown object.

    At the National Physics Laboratory in England a measurement of the gravitational acceleration g was made by throwing a glass ball straight up in an evacuated tube and letting it return, as shown in the Figure. The time interval between the two passages across the lower level is equal to ∆TL =...
  17. G

    Calculating Pressure due to Containment of Hydrogen Ions

    I’ve been doing some hobbyist-research and modelling in MATLAB relating to the confinement of hydrogen ions (pure protons). I have written a few scripts including one to determine an estimate of the work required to compress a large number of H+ ions, by considering an evenly spaced stationary...
  18. P

    Calculating final kinetic energy from change in velocity by percent

    The kinetic energy of a car is 1.02 × 105 J. If the car s speed increases by 28.2%, then what is the new kinetic energy of the car? I set up the ratio Kf/Ki=Vf2/Vi2 Vf= 1 + 28.2/100)2Vi2 this cancels the right side of the equation out to (1.282)2 to find Kf, I then multiplied both sides by Ki...
  19. J

    Calculating Loss of Kinetic Energy

    Good morning all, I have another Kinetics problem that has me stumped at the moment. I just cant see the way to solve the problem posed. The problem in question is as follows - Problem A Neutron with mass m makes a head-on Elastic Collision with a Nucleus of mass M, which is initially...