Maths mechanics last one - i find these so confusing.?

  • Thread starter Thread starter cesc0836
  • Start date Start date
C

cesc0836

Guest
A spring balance hangs from the roof of a lift. A case of mass m kg is hung from the spring balance by a string. While the lift is accelerating upwards with magnitude a ms^-2, the reading on the balance is 12.5kg; when the lift is moving downwards with an acceleration of a ms^-2 the reading is 9kg. Find the values of m and a.
 
12.5g - mg = ma ......(1)
mg - 9g = ma......(2)
Subtract the second equation from the first,
12.5g - 2mg + 9g = 0
m = (12.5+9)/2 = 10.75 kg
a = (12.5g - mg)/m = 1.595 m/sec^2
 
12.5g - mg = ma ......(1)
mg - 9g = ma......(2)
Subtract the second equation from the first,
12.5g - 2mg + 9g = 0
m = (12.5+9)/2 = 10.75 kg
a = (12.5g - mg)/m = 1.595 m/sec^2
 
Back
Top