Question

Two blocks of masses 4kg and 2 kg are connected to the ends of a string which passes over a massless frictionless pulley . The total downward thrust on the pulley is nearly

Answer 1

Answer:

54

Explanation:

  Given Two blocks of masses 4 kg and 2 kg are connected to the ends of a string which passes over a mass less friction less pulley . The total downward thrust on the pulley is nearly

Given forces acting on mass m1 are the weight acting downwards = m1g,  

tension on string acting upwards is T and force acting downwards is m1a

So m1g – T = m1a -----------1

Given forces acting on mass m2 are the weight acting downwards = m2g,  

tension on string acting upwards is T and force acting downwards is m2a

So T – m2g = m2a ------------2

Adding 1 and 2 we get

So a = (m1 – m2)g / (m1 + m2)

Now by subtracting we get

T = 2 m1 m2 g / m1 + m2

Force on pulley is 2T

                = 2 x 2 m1 m2 g / (m1 + m2)

                = 4 x 4 x 2 x 10 / 4 + 2

              = 320 / 6

             = 53.33

             ≅ 54 N