Mechanical Engineering - Engineering Mechanics - Discussion

Discussion Forum : Engineering Mechanics - Section 4 (Q.No. 2)
2.
If tension in the cable supporting a lift moving downwards is half the tension when it is moving upwards, the acceleration of the lift is
g/2
g/3
g/4
none of these
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
38 comments Page 4 of 4.

ANup said:   9 years ago
While going up,

T1-mg=ma ------------- (1)

While going down,

Mg-t2=ma --------------- (2)

Solving 1 & 2,

2(mg-ma)-mg=ma.

Or, mg-2ma=ma.

Or, mg=3ma.

Or, a=g/3.

Purushottam said:   9 years ago
@Gurdeep @Gaurav.

Problem shows that;
m(g-a) = m(g+a)/2.

Kafeel Ahmad khan said:   8 years ago
mg-T= ma ----> (1)
2T-mg=ma ----> (2).

Putting the value of T in equation (2).
2(mg-ma)-mg = ma,
2mg-2ma-mg = ma,
mg = 3ma,
a = g/3.

Badan singh said:   8 years ago
Yes, the correct answer is g/3.

Dheeraj kumar said:   8 years ago
g/3 if the acceleration is constant otherwise, option D.

Rk reddy said:   8 years ago
g/3 is the answer.

A.jay said:   8 years ago
Answer is g/3. The question doesn't asks about direction of lift so there is no point of negative g/3.

Guin said:   8 years ago
If the tension is being half on moving downwards then surely be double on upward.


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