Question

Figure shows three blocks that are being pulled along a smooth horizontal surface. The masses of the blocks

are shown in figure and tension force in cord connecting A and B = 120 N. The pulling force Fis:
A SZONB
C С
4kg 4kg 2kg
Fu
Smooth
(C) 125 N
(A) 50 N
(B) 100 N
(D) 200 N​

Answer 1

The pulling force F is 200 N

Step-by-step explanation:

We note that the tension in a rope between two or three blocks is given by the relation;

Where we have;

m₁ → T₁ → m₂ → T₂ → m₃ → F

`T_1 = (m_1)/(m_1 + m_2 + m_3) * F`

`T_2 = (m_1 + m_2)/(m_1 + m_2 + m_3) * F`

m₁ = 2 kg

m₂ = 4 kg

m₃ = 4 kg

T₂ = 120 N

Therefore, by substitution, gives;

2 kg → T₁ → 4 kg → 120 N → 4 kg → F

`120 \ N = (2 \ kg + 4 \ kg)/(2 \ kg+ 4 \ kg+ 4 \ kg) * F = (6 \ kg)/(10 \ kg) * F`

F = 120 N × (10 kg)/(6 kg) = 200 N

The pulling force F = 200 N.