Question

Three blocks of masses $m _ { 1 } , m _ { 2 }$ and $m _ { 3 }$ are connected by massless strings as shown on a frictionless table. They are pulled with a force $T _ { 3 } = 40 \mathrm {~N}$ . If $m _ { 1 } = 10 \mathrm {~kg} , m _ { 2 } = 6 \mathrm {~kg}$ and $m _ { 3 } = 4 \mathrm {~kg}$ , the tension $T _ { 2 }$ will be

• A. 20 N
• B. 40 N
• C. 10 N
• D. 32 N

Answer 1

Answer: (D)

32 N

Answer 2

$T _ { 2 } = \left( m _ { 1 } + m _ { 2 } \right) \times \frac { T _ { 3 } } { m _ { 1 } + m _ { 2 } + m _ { 3 } } = \frac { ( 10 + 6 ) \times 40 } { 20 }$ $= 32 \mathrm {~N}$