Question

The block C shown in the figure is ascending with an acceleration a
not shown here. The bodies A and B of masses 10 kg and 5 kg respectively, assuming pulleys and
3 m/s by means of some motor
strings are massless and friction is absent everywhere. Then find acceleration of body A.
​

Answer 1

Answer:

aA=−1m/s2

Explanation:

First see the picture in order to understand the scenario;

Focussing on the net forces diagrams;

Net force acting on Block A will be;

mg−2T=maA

10g−2T=10aA (1)

Net force acting on Block B will be;

mg−T=maB

5g−T=5aB (2)

Mutipying eq(2) by 2 and then subtracting it from eq(1), we will eliminate T

10aA−10aB=0

⇒aA=aB

Now l1+l2+l3=constant

yE+yA+yA+yB= costant

Differentiating twice w.r.t. time,

a+2aA+aB=0

2aA+aB=−3

or 3a0=−3

⇒aB=−1m/s2,

aA=−1m/s2

aA=aB=1m/s2 upwards

Answer 2

Answer:

aA=−1m/s2

Explanation:

First see the picture in order to understand the scenario;

Focussing on the net forces diagrams;

Net force acting on Block A will be;

mg−2T=maA

10g−2T=10aA (1)

Net force acting on Block B will be;

mg−T=maB

5g−T=5aB (2)

Mutipying eq(2) by 2 and then subtracting it from eq(1), we will eliminate T

10aA−10aB=0

⇒aA=aB

Now l1+l2+l3=constant

yE+yA+yA+yB= costant

Differentiating twice w.r.t. time,

a+2aA+aB=0

2aA+aB=−3

or 3a0=−3

⇒aB=−1m/s2,

aA=−1m/s2

aA=aB=1m/s2 upwards