Join TSR now and get all your revision questions answeredSign up now

don't understand the markscheme? Watch

    • Thread Starter
    Offline

    3
    ReputationRep:
    Hello! I was doing a WJEC Additional Science P2 Paper and this answer is tripping me up...
    The question states

    'One of the world's tallest roller coasters has an initial peak of height 140m. After reaching the top, the car first falls to a height 50m above the ground before it continues on its journey
    -the mass of the car and passengers is 1200kg, use equations from page 2 to calculate the theoretical maximum velocity of the car after this first fall (g=10m/s²)"

    Now, I did
    PE = mgh
    = 1200 x 10 x (140-50) = 1080000J

    then PE=KE, so KE = 1/2mv²
    1080000 = 1/2 x 1200 x v²
    I rearranged and got 21.21 etc
    But the mark scheme says the velocity is double, 42.4 m/s

    help me out, please???
    Offline

    3
    ReputationRep:
    (Original post by CresentHan)
    Hello! I was doing a WJEC Additional Science P2 Paper and this answer is tripping me up...
    The question states

    'One of the world's tallest roller coasters has an initial peak of height 140m. After reaching the top, the car first falls to a height 50m above the ground before it continues on its journey
    -the mass of the car and passengers is 1200kg, use equations from page 2 to calculate the theoretical maximum velocity of the car after this first fall (g=10m/s²)"

    Now, I did
    PE = mgh
    = 1200 x 10 x (140-50) = 1080000J

    then PE=KE, so KE = 1/2mv²
    1080000 = 1/2 x 1200 x v²
    I rearranged and got 21.21 etc
    But the mark scheme says the velocity is double, 42.4 m/s

    help me out, please???
    Yeah I got 42.43 as well - probably you're not rearranging properly

    1080000 = 1/2 x 1200 x v2
    2160000 = 1200 x v2
    1800 = v2
    v = sqrt (1800) = 42.43
 
 
 
Poll
How are you feeling about Results Day?

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.