Question

Two blocks of masses 8kg and 4kg respectively are connected by a string as shown in figure. Calculate their accelerations if they are initially at rest on the floor, after a force of 100N is applied on the pulley in the upward direction.(g=10 m/s.sq.)

Answer 1

force applied on the pulley will be 100 N

since pulley is ideal so we can say tension in the string must be 50 N

now we will have

for 4 kg block

$F_t - mg = ma$

plug in all values

$50 - 40 = 4a$

$10 = 4a$

$a = 2.5 m/s^2$

weight of other block of mass 8kg is 80 N

its weight is more than the tension in the string so this block will remain at rest and its acceleration must be ZERO

Answer 2

Answer:

Explanation:force applied on the pulley will be 100 N

since pulley is ideal so we can say tension in the string must be 50 N

now we will have

for 4 kg block

plug in all values

weight of other block of mass 8kg is 80 N

its weight is more than the tension in the string so this block will remain at rest and its acceleration must be Zero