# Look at the attachement and answer the questyions

1
by rajusetu

2015-05-01T02:40:57+05:30

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14.
T Cos 30 =  1 kg * a
30 N - T cos 30 = 2 kg * a
=>  3 a = 30      =>  a = 10 m/sec/sec
=>  T  = 20/√3  N
Normal reaction:    mg - T sin 30 = 1 * 10 - 20/√3 * 1/2 = 10 - 10/√3  N
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15.
m1 = 2 kg        m2 = 5 kg
F - (m1 + m2) g = (m1 + m2 ) a      =>  F - 70 = 7 a
So the pulley moves up only if  F > 70 Newtons.

F = 70 N,  then accelerations are both 0, as the pulley still does not move up.
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16.
m2 g = tension    as m2 is at rest.
m1 g Sin Ф - tension        as m1 is at rest.
m1 Sin Ф = m2
verify the options by substitution.
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17
F1 = 10 N,  F2 = 20 N
F1 Cos 60  + F2 = 25 N     ---  in x direction
F1 Sin 60 = 5√3 N         ---  in the y direction,  as block is at rest.
resultant  =  √ [25² + (5√3)² ] = 26.46  N
the result is supposed to be an integer???/
Are you expected to write only the force in the x direction ???
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18.   m1 = 3 kg,        m2 = 2kg
F cos 60 =  m1 a - T
T =  m2  a
a = F * Cos 60  /(m1+m2)  = 1 m/s/s
T = 2 N
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19.
F - mg = ma
F - 2 * 10 = 2 * 5
F = 30 N
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20.
F - mg  = m a = - m g          as  F is upwards, and a = -g  downwards
F = 0 N
click on thanks (azur blue button above please
yep sir