Turn on thread page Beta
    • Thread Starter
    Offline

    18
    ReputationRep:
    How should I work out this question?

    Q)
    Energy stored per unit mass (Jkg^-1)

    Modem spring steel - 130
    Tendon in leg - 2500
    Rubber cord. - 8000

    Show that a car of mass 1200kg would need steel springs of total mass approximately equal to 3kg to store energy when it encounters pot-holes of depth 3 cm
    (3 marks)

    I appreciate all solutions and suggestions a lot!
    Offline

    17
    ReputationRep:
    (Original post by Iluv2edgedsword)
    How should I work out this question?

    Q)
    Energy stored per unit mass (Jkg^-1)

    Modem spring steel - 130
    Tendon in leg - 2500
    Rubber cord. - 8000

    Show that a car of mass 1200kg would need steel springs of total mass approximately equal to 3kg to store energy when it encounters pot-holes of depth 3 cm
    (3 marks)

    I appreciate all solutions and suggestions a lot!
    Hi there, so you need to think about the change in potential energy when the car drops 3 cm
    So as you know the potential energy change will be  E=mgh = 1200\times 10 \times 0.03 = 360 J
    Thus the spring needs to absorb 360 J worth of energy.
    This is equivalent to 360/130= 2.76 kg which is about 3, I guess
    • Thread Starter
    Offline

    18
    ReputationRep:
    (Original post by langlitz)
    Hi there, so you need to think about the change in potential energy when the car drops 3 cm
    So as you know the potential energy change will be  E=mgh = 1200\times 10 \times 0.03 = 360 J
    Thus the spring needs to absorb 360 J worth of energy.
    This is equivalent to 360/130= 2.76 kg which is about 3, I guess
    Grateful for thine help!
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: November 18, 2017
Poll
Do you think parents should charge rent?

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.