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  • Period of oscillation again?

    Why is period not dependant on amplitude? Is it because as amplitude increases, strain energy increases, and the strain energy will be converted to kinetic energy hence v is just made to be larger so it moves faster to oscillate at the same period? is this correct/logical? 

    1 AnswerPhysics2 weeks ago
  • Specific latent heat ?

    Why is specific latent heat = (rate of supply of energy)/(rate of loss of mass) ??

    Q=mL

    if we plot a graph of Q vs m, the gradient is L

    but if we heat water with a constant power P in a time of t and plot a graph of mass vs time, then why is L = (rate of supply of energy)/(rate of mass loss) ?

    I understand that Q=Pt, so it takes Pt amount of energy to reduce the mass from m1 to m2 in a time of t. But I'm not sure why the formula is like that? I didn't think m here works like the ∆T in Q=mc∆T, or does it? 

    1 AnswerPhysics2 weeks ago
  • period of oscillation ?

    if period of oscillation is not dependent on amplitude, then how come for simple harmonic motion we have

     a= -(2π/T)²x 

    which means acceleration is dependent on x which is displacement (basically amplitude) so period clearly depends on amplitude based on this equation? 

    2 AnswersPhysics2 weeks ago
  • Pushing a piston, but the molecules produce the same force ?

    If the piston in a bicycle pump is pushed inwards but the temperature is kept constant, then more molecules will hit the piston in each second

    but why will each collision produce the same force? "more molecules will hit the piston each second" shouldn't that mean F increases? I know that v is kept constant here because T is kept constant.

    3 AnswersPhysics3 weeks ago
  • Newton's third law?

    I learnt that the huge air pressure around us does not crush us because the air inside our bodies presses outwards with an equal and opposite force.

    But I don't understand. Newton's third law says the forces must act on different objects. 

    So the forces are 

    1. Outside air on body

    2. Air inside body on outside air

    So since they act on different object, the force of the outside air on the body cannot be "cancelled out" by the force of the air inside the body on the outside air. So why do we not collapse under air pressure? The text made it seem like the forces cancel out, I'm very confused!

    Thank you

    6 AnswersPhysics3 weeks ago
  • Terminal velocity question?

    when an object falls under gravity, I understand that the air resistance increases with speed, and since velocity is increasing with time (decreasing gradient because of air resistance) the air resistance on the object increases with time too and they will eventually cancel each other out. So is this why the air resistance can never be higher than the weight of the object (or else the object would start flying after reaching terminal velocity)? Because air resistance is proportional to speed, at terminal velocity speed is constant so air resistance cannot get higher. True?

    8 AnswersPhysics1 month ago
  • Newton's third law?

    I learnt that a helicopter lifts because of Newton's third law. Its blades pushes the air below it with a force F and simultaneously the air pushes the helicopter upwards with the same force F.

    Since F=ma, then the helicopter experiences acceleration F/m.

    Is this true? 

    1 AnswerPhysics2 months ago
  • When gas is compressed why does kinetic energy increase?

    I thought of it like this

    from the first law of thermodynamics ∆U=q+w 

    since gas is compressed and no heat is provided to the system, q=0 and there is work done on the s

    ystem, so +w

    so ∆U=+w hence there is a rise in temperature of the gas (since internal energy U is a function of temperature)

    so since temperature is the measure of kinetic energy of molecules, hence there is rise in kinetic energy too?

    Or from the fact that there is work done on the system,

    work done converted into kinetic energy

    so there is increase in kinetic energy

    is my logic correct? or can someone explain it better?

    4 AnswersPhysics2 months ago
  • Boyle's Law and the first law of thermodynamics?

    Boyle's law states pV= constant provided the temperature of the gas remains constant.

    But the first law of thermodynamics ∆U=q+w tells us that when a gas is compressed there is ∆U hence a rise in temperature.

    So what am I missing here? How is Boyle's law consistent with this first law of thermodynamics?

    2 AnswersPhysics2 months ago
  • Does face mask protect you or others?

    By the way, I'm talking about the medical face mask (the one with a blue side and a white side).

    I can't find a solid answer from the internet. One source said that face masks are only effective in protecting others from you if you have the virus, but it does not protect you from other people if other people aren't wearing a mask. Meaning it's hard for particles to leave the mask, but easy for particles to enter the mask?

    If the mask stops particles from your mouth leaving the mask which you wear, then shouldn't that mean that the mask should be able to also prevent particles from outside the mask from entering? Why is it only one-way?

    And another question is it any different from a fabric mask?

    Thanks. Very confused.

    15 AnswersMedicine2 months ago
  • Addressing a PhD?

    My math teacher recently completed her PhD but she has yet to graduate. I've been calling her "Ms". Do I start calling her Dr now even though she hasn't graduated, or should I ask her if she would like me to call her by Dr?

    TIA

    1 AnswerPolls & Surveys3 months ago
  • Should suicide be illegal or legal, and why?

    My opinion: The only good rationale behind the criminalisation which I found is that it is for those who use suicide as an easy escape to avoid their other punishment(s), which in turn will make them face heavier repercussions.

    11 AnswersLaw & Ethics9 months ago
  • Which country is the smartest?

    Statistically USA has produced the most PhD graduates

    5 AnswersPolls & Surveys10 months ago
  • What type of person do you hate most?

    I hate people who take advantage of others

    119 AnswersPolls & Surveys10 months ago
  • Which country is the best country in your opinion?

    Just name one country and please don't say some sh*t like "eVeRy CoUntRy iS GoOD iN ThEiR OwN WaY"

    18 AnswersPolls & Surveys10 months ago
  • Thoughts on people who are proud of their race?

    What would you think of someone who "flaunts" the fact that they're half south korean, half caucasian?

    5 AnswersPolls & Surveys10 months ago
  • Find the coefficient of x^(-16) in the expansion of (x^2 - 1/x)^25?

    Find the coefficient of x^(-16) in the expansion of (x^2 - 1/x)^25

    Please show different methods of solving this, thanks in advance

    5 AnswersMathematics1 year ago