Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    2
    ReputationRep:
    The Q is a Mens race is 60m long, and was carried out in 6.41s.Assuming the race was carried out under constant acceleration, calculate the acceleration of the runner and his speed at the end of the race?

    I kinda forgot what constant acceleration means, I just thought I dont have enough info to work out anything?
    Online

    13
    ReputationRep:
    Constant acceleration means you can use suvat equations

    you know s, u and t
    Offline

    22
    ReputationRep:
    (Original post by SunDun111)
    The Q is a Mens race is 60m long, and was carried out in 6.41s.Assuming the race was carried out under constant acceleration, calculate the acceleration of the runner and his speed at the end of the race?

    I kinda forgot what constant acceleration means, I just thought I dont have enough info to work out anything?
    Constant acceleration means you can use SUVAT.

    You know:

    s=60
    u=0 (has to start from rest, it's a race)
    v=?
    a=?
    t=6.41

    So what equations can you use to find a? s = ut + 1/2at^2 seems pretty useful to me...
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by Zacken)
    Constant acceleration means you can use SUVAT.

    You know:

    s=60
    u=0 (has to start from rest, it's a race)
    v=?
    a=?
    t=6.41

    So what equations can you use to find a? s = ut + 1/2at^2 seems pretty useful to me...
    Ok thanks
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by Zacken)
    Constant acceleration means you can use SUVAT.

    You know:

    s=60
    u=0 (has to start from rest, it's a race)
    v=?
    a=?
    t=6.41

    So what equations can you use to find a? s = ut + 1/2at^2 seems pretty useful to me...
    Ok I worked out the acceleration as 2.93, and the speed he finished the race as 18.73ms but the next part of the question says, assume that in a 100m race the runner accelerates for the next 60m and completes the race by running the next 40m in the speed you calculated for the end of the 60m. Calculate the time for the athlete to complete the race.

    I would think you have to use SUVAT just for the final 40m? But would U = 0?
    Offline

    22
    ReputationRep:
    (Original post by SunDun111)
    Ok I worked out the acceleration as 2.93, and the speed he finished the race as 18.73ms but the next part of the question says, assume that in a 100m race the runner accelerates for the next 60m and completes the race by running the next 40m in the speed you calculated for the end of the 60m. Calculate the time for the athlete to complete the race.

    I would think you have to use SUVAT just for the final 40m? But would U = 0?
    No... if he runs the next 40m at a speed of 18.73, then it's literally just time = distance/speed = 40/18.73
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by Zacken)
    No... if he runs the next 40m at a speed of 18.73, then it's literally just time = distance/speed = 40/18.73
    Thanks done it, another Q us a sprinter starts from rest, accelerates at 2ms and for the frist four seconds of the race the sprinter moves along a strraight line. Find the distance travelled byt the sprinter in the first 4 seconds, find the speed of the sprinter at the end of the first 4 seconds, the sprinter travels at this speed for the remainder of the race, he travels a total distance of 100m find the total time that he takes th complete the way.

    I got the distance as 16m and speed after 4 seconds as 8ms. But I cant do the final bit, how would i break it down?
    Offline

    22
    ReputationRep:
    (Original post by SunDun111)
    Thanks done it, another Q us a sprinter starts from rest, accelerates at 2ms and for the frist four seconds of the race the sprinter moves along a strraight line. Find the distance travelled byt the sprinter in the first 4 seconds, find the speed of the sprinter at the end of the first 4 seconds, the sprinter travels at this speed for the remainder of the race, he travels a total distance of 100m find the total time that he takes th complete the way.

    I got the distance as 16m and speed after 4 seconds as 8ms. But I cant do the final bit, how would i break it down?
    If he's already travelled 16 metres in 4 seconds, it means he has 100 - 16 metres left that he runs at 8 metres per second.

    So how long does he take to run (100-16) metres at 8 metres per second? Same formula. Time = distance/speed.
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Brussels sprouts
    Useful resources

    Make your revision easier

    Maths

    Maths Forum posting guidelines

    Not sure where to post? Read the updated guidelines here

    Equations

    How to use LaTex

    Writing equations the easy way

    Student revising

    Study habits of A* students

    Top tips from students who have already aced their exams

    Study Planner

    Create your own Study Planner

    Never miss a deadline again

    Polling station sign

    Thinking about a maths degree?

    Chat with other maths applicants

    Can you help? Study help unanswered threads

    Groups associated with this forum:

    View associated groups
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • 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

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