Turn on thread page Beta
    Offline

    5
    ReputationRep:
    (Original post by Exams987)
    isn't the formula S=0.5(v+u)t
    U was 0 in the question as it was from rest
    Offline

    11
    ReputationRep:
    How has everyone prepared for this? If u do the 10 past papers, how much of the paper will be stuff never seen before on past papers?
    Offline

    6
    ReputationRep:
    In a projectile, if air resisitance is taken into account, will that effect both the horizontal and vertical distance travelled by object? I feel like the vertical distance is not effected, can anyone clarify?
    Offline

    7
    ReputationRep:
    (Original post by boyyo)
    In a projectile, if air resisitance is taken into account, will that effect both the horizontal and vertical distance travelled by object? I feel like the vertical distance is not effected, can anyone clarify?
    Only horizontal
    Offline

    2
    ReputationRep:
    (Original post by boyyo)
    In a projectile, if air resisitance is taken into account, will that effect both the horizontal and vertical distance travelled by object? I feel like the vertical distance is not effected, can anyone clarify?
    Distance wont be affected in projectile questions as it hits the floor...but air resistance does affect downwards force just as much as horizontal force. SO actually air resitance would both increase and decrease the length travelled horizontally, as the time taken to hit the floor would be longer, but its horizontal speed would decline faster......this is why they dont really include air resitance
    Offline

    3
    ReputationRep:
    (Original post by GdotMdot)
    U was 0 in the question as it was from rest
    in the question was the motion linear ?

    if the motion is linear then i think you use s=vt
    Offline

    7
    ReputationRep:
    (Original post by TSRPAV)
    Only horizontal
    e.g throw a ball horizontally from 1m off the ground when the wind is against you, it will be displaced 1m vertically from you when its on the ground,however horizontally it will be displaced dependant on how strong the wind is e.g xm

    throw a ball in a vacuum container horizontally from 1m off the ground it will still be displaced 1m vertically from you when on the ground but will be displaced further horizontally at something like 3xm
    Offline

    6
    ReputationRep:
    (Original post by philo-jitsu)
    Distance wont be affected in projectile questions as it hits the floor...but air resistance does affect downwards force just as much as horizontal force. SO actually air resitance would both increase and decrease the length travelled horizontally, as the time taken to hit the floor would be longer, but its horizontal speed would decline faster......this is why they dont really include air resitance
    I kind off get what your saying, but say q2 here:
    https://5505b400f275fd9f29b9b4679ca5...%20Physics.pdf

    Part c asks why it wouldnt travel that far, and it mentions how you said the horizontal speed declines etc. So the air resistance causes the horizontal spped to fall and therefore the distance reached to be less?
    Offline

    11
    ReputationRep:
    any ideas?
    (Original post by ryandaniels2015)
    How has everyone prepared for this? If u do the 10 past papers, how much of the paper will be stuff never seen before on past papers?
    Offline

    5
    ReputationRep:
    (Original post by Exams987)
    in the question was the motion linear ?

    if the motion is linear then i think you use s=vt
    Oh i see, acceleration would be constant as it is for vertical.
    Offline

    11
    ReputationRep:
    For this question why don't you use the displacement 3 to calculate time taken?
    Attached Images
     
    Offline

    2
    ReputationRep:
    (Original post by ryandaniels2015)
    For this question why don't you use the displacement 3 to calculate time taken?
    The question says 'speed' of 6.7ms....which is a magnitude not a vector, direction doesnt come into it.
    Offline

    11
    ReputationRep:
    (Original post by philo-jitsu)
    The question says 'speed' of 6.7ms....which is a magnitude not a vector, direction doesnt come into it.
    But the bike has travelled upwards 6.7m/s so wouldn't u consider vertical height?
    Offline

    2
    ReputationRep:
    (Original post by boyyo)
    I kind off get what your saying, but say q2 here:
    https://5505b400f275fd9f29b9b4679ca5...%20Physics.pdf

    Part c asks why it wouldnt travel that far, and it mentions how you said the horizontal speed declines etc. So the air resistance causes the horizontal spped to fall and therefore the distance reached to be less?
    Yep, the friction acts directly against the motion vector.....so its horizontal and vertical really....but for these questions just say air resistance produces a force against the motion of the object, which decreases the velocity resulting in less distance travelled....which is pretty much what you said I am just realizing lol
    Offline

    2
    ReputationRep:
    (Original post by ryandaniels2015)
    But the bike has travelled upwards 6.7m/s so wouldn't u consider vertical height?
    Vector includes direction...speed doesnt,
    Offline

    7
    ReputationRep:
    (Original post by boyyo)
    I kind off get what your saying, but say q2 here:
    https://5505b400f275fd9f29b9b4679ca5...%20Physics.pdf

    Part c asks why it wouldnt travel that far, and it mentions how you said the horizontal speed declines etc. So the air resistance causes the horizontal spped to fall and therefore the distance reached to be less?
    kinda, basically if you resolve horizontally in this "theory" without air resistance there is no resistive forces to decelerate(slow it down) and it will not be accelerating as there is no thrust proving acceleration(no overall force as no acceleration so only v=s/t applies)so we use the impulse velocity, which is what it is travelling as it left the racket and as the time of horizontal and vertical displacement is the same/constant (read about monkey-hunter model) we can use v=s/t so v is proportional to s (as t is constant).so basically all values are max

    When air resistance occurs in practice horizontally: the time to displace horizontally and vertically is still the same(constant) however there is a resistive drag force on the ball which causes it to decelerate, as there is no thrust on the ball after it has left the racket the only horizontal force acting on it is the air resistance which will be large and slowly decrease(decelerate the ball) until zero when it no longer moves horizontally So as the ball is decelerating its mean velocity is less. so v=s/t (where t is constant) if v decreases, t is constant then s must decrease
    Offline

    16
    ReputationRep:
    how do you use a mirror to reduce parallax error?
    Offline

    6
    ReputationRep:
    (Original post by philo-jitsu)
    Yep, the friction acts directly against the motion vector.....so its horizontal and vertical really....but for these questions just say air resistance produces a force against the motion of the object, which decreases the velocity resulting in less distance travelled....which is pretty much what you said I am just realizing lol
    lol thanks
    Offline

    11
    ReputationRep:
    (Original post by philo-jitsu)
    Vector includes direction...speed doesnt,
    Thanks I understand, so then why does it matter if u use 3m or 50m for distance?
    Offline

    7
    ReputationRep:
    (Original post by ryandaniels2015)
    any ideas?
    not much, done like 6 of the papers and i do maths mechanics which helpsish
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: August 19, 2016

University open days

  1. University of Cambridge
    Christ's College Undergraduate
    Wed, 26 Sep '18
  2. Norwich University of the Arts
    Undergraduate Open Days Undergraduate
    Fri, 28 Sep '18
  3. Edge Hill University
    Faculty of Health and Social Care Undergraduate
    Sat, 29 Sep '18
Poll
Which accompaniment is best?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.