Question

Two masses 40 kg and 30 kg are connected by a weightless string passing over a frictionless pulley as shown in the following figure. The tension in the string will be -

• A. 188 N
• B. 368 N
• C. 288 N
• D. 168 N

Answer 1

Answer: (D)

168 N

Answer 2

T = $\frac { \mathrm { m } _ { 1 } \mathrm {~m} _ { 2 } } { \mathrm {~m} _ { 1 } + \mathrm { m } _ { 2 } }$ (sin a + sin b).g

= $\frac { ( 40 ) ( 30 ) } { 40 + 30 } \left( \frac { 1 } { 2 } + \frac { 1 } { 2 } \right) \cdot g$ = $\frac { 1200 \mathrm {~g} } { 70 }$

= 168 N