Just an addition on Question 9 Since the balls are identical in shape and size they have the same upthrust as U = density of liquid x g x volume of ball, hence upthrust remains the same, but as the heavier ball has a greater mass, hence a greater weight, so for resultant force to be zero the drag force increases and the velocity will also increase hence heavier ball falls at a larger speed,
@joy4467 Ok, we know that F= ma, where F is the resultant force, so since the drag force and upthrust(Acting upwards) are equal to the weight (acting downwards), then the resultant force will be zero, hence the acceleration is zero. Now like I said as the ball is heavier it means its weight is greater and since the upthrust is constant ad the volume is constant, it means that the only thing that will increase is the drag force hence since the drag force is linked to the velocity, the heavier ball will fall at a larger speed,
@joy4467 I hope it makes sense, if there is anything unclear you can point it out or any other question you did not understand, I will be happy to reply
Thank you so much for pointing that out, I did say 0.50, but I wrote the wrong thing down when I was writing it, must have slipped my mind, the answer was indeed 400 = 800*0.5, but I just wrote it wrongly although thr answer is correct, If you have any other questions please do ask, I will be happy to help, or any question paper you might need assistance on or a video to be made
Ok, so the centre of weight is the point on an object where all its weight is assumed to be acting, so if it is a uniform metre rule all the weight will be acting at the centre because that is the geometrical centre so the centre if a metre rule is at the 50cm mark because that is where all the weight well be acting
I hope it makes sense, if you have any questions on this paper, any parr that is unclear or on any of my other videos please just put it in the comment secton and I will respond, are you a candidate writing their A levels this year or not?
Thank you very much for pointing that out, the answer is indeed C, I made a mistake by circling D but I put a tick on D and if you listen to the audio I do explain why C is the answer, but thanks anyway for that I appreciate your keen and attentive eye👍👍
