If a man is measuring his actual weight by accurate weighing machine as shown in the figure. The mass of man 60 kg.
mass of weighing machine is 20 kg and mass of lift is 30 kg (pulley is smooth and string is massless) (Take g = 10 ms
Question(17)
Acceleration of the lift is
30 ms - 2
78.5 ms - 2
C
110 ms - 2
CDMISYT
CLEAR RESPONSE
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Answers
Answer:
Pls sent the question picture so we could understand better
Answer:
So, he should exact 1800N force on the rope to get correct reading.
Explanation:
(i) Given, Mass of man =60kg [Ref. image 1]
Let R ′= apparent weight of man in this case.
Now, R ′+T−60g=0 [From FBD of man]
⇒T=60g−R ′...(i)
T−R′−30g=0 ...(ii) [From FBD of box]
⇒60g−R′−R′−30g=0 [From (i)]
⇒R ′=15g The weight shown by the machine is 15kg.
(ii) To get his correct weight suppose the applied force is T ′and so, accelerates upward with 'a'. In this case, given that correct weight =R=60g, where $$g = acc^n due to gravity
From the FBD of the manT 1+R−60g−60a=0
⇒T 1 −60a=0 [∴R=60g]
⇒T 1=60a .....(i)
From the FBD of the boxT 1 −R−30g−30a=0
⇒T 1 −60g−30g−30a=0
⇒T 1 −30a=90g=900
⇒T 1 =30a−900 ...(ii)
From eqn. (i) and eqn.(ii) we get T 1 =2T 1−1800T 1=1800N.
∴ So, he should exact 1800N force on the rope to get correct reading.
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