Recent content by komender

  1. K

    How to correctly identify r and r' in electromagnetics

    Homework Statement This is more of a general problem that I noticed I constantly fail to get right, and seems like something quite basic in vector calculus but it mostly affects me in my electromagnetism class. Whenever I try to work on a problem that involves figures and objects in space, I am...
  2. K

    Identifying Freefall: Analyzing Graphs for Acceleration

    I meant the bottom graph, the acceleration vs. time graph. It is the one that is marked off in grey. Does it mean that its in free fall when the acceleration is 9.81, i.e when the curve of the a/t graph is a constant?
  3. K

    Identifying Freefall: Analyzing Graphs for Acceleration

    Homework Statement So I am doing my lab, when I realize that I am not sure where the freefall occurs. I collect the data for a ball tossed in the air, and using a vernier motion detector, I found the graphs for displacement, velocity and acceleration (attached). second peak) Homework...
  4. K

    Constant velocity and net force

    But aren't you looking at the net force that is generated from the man's push? If I would only account for the force that was exerted by the man, than I would get 225cos15*12 = 2608J, but the correct answer is 320 because I'm taking into account the normal force which is mg + 225sin15 = 794...
  5. K

    Constant velocity and net force

    but then the question says that the box is moving at constant velocity when it was pushed 12m...
  6. K

    Constant velocity and net force

    Homework Statement A man is pushing a 75 kg crate at constant velocity a distance of 12 m across a warehouse. He is pushing with a force of 225 N at an angle of 15° down from the horizontal. The coefficient of friction between the crate and the floor is 0.24. How much work did the man do...
  7. K

    Crumple zone in cars and ways to measure its effectiveness

    Oh you mean the actual number... I see what you mean. I thought you asked what is the source of this force. So its not the force that comes from the crash that is important, but the deceleration. But what about the energy that is generated from the collision? Wouldn't that have a factor as...
  8. K

    Crumple zone in cars and ways to measure its effectiveness

    Wouldn't that simply be the reaction force of the wall?
  9. K

    Crumple zone in cars and ways to measure its effectiveness

    Do you mean that I should use the deceleration that I found and multiply it by the car's mass to get the force that acts on the people? So what is the significance of the force that I calculated using the momentum and impulse equation? is it just the force that the car experiences? and if so...
  10. K

    Crumple zone in cars and ways to measure its effectiveness

    Homework Statement I am trying to prove the efficiency of crumple zone in a presentation, but I think that I'm am doing something wrong. Basically I'm a grade 12 physics student, and I am suppose to present crumple zone. I understand that we need to impulse and momentum in here, and I tried...
  11. K

    Interview with a mechanical engineer

    Hello, I wasn't sure where to put this questionnaire, because it says on top do not post homework, but then again, I need to ask real engineers and the other forum is for undergraduates ( I think). Anyway I need to interview a mechanical engineer for my careers class, and I had been hoping that...
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