Q)A person is standing in a lift on a bathroom scale moving upwards with an acceleration of 2ms^-2.The mass of the person is *x* kg.The lift suddenly decelarates upwards with 6ms^-2 and comes to rest after travelling another 10 metres.The reading on the scale before the decelaration was twice the reading just after the decelaration.Find the value of *x* if the difference between the two scale readings was 55kg.THANKS
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M1 Edexcel W=mg problem?? watch
- Thread Starter
- 24-01-2010 14:59
- 25-01-2010 01:14
What you need to do for this question is start by drawing two free body force diagrams for the person for each stage in the lift. Remember that if you are told the acceleration of the lift, this will be the same as the acceleration of the person. Also, the normal contact force on the person will be the same as the reading on the scales multiplied by g. You can in fact immediately find the two scales readings using the fact that one is double the other, and that their difference is 55kg.