With what acceleration ‘a’ should the box of figure moving up so that the block of mass M exerts a force 7 Mg/4 on the floor of the box?

Question

With what acceleration ‘a’ should the box of figure moving up so that the block of mass M exerts a force 7 Mg/4 on the floor of the box? <img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/8bad145ae47a3b74703860365a05817b-.png" /> (A) g/4 (B) g/2 (C) 3g/4 (D) 4g

Tardigrade Admin · Accepted Answer

FBD of M: If M exerts force F = 7 Mg/4 on floor, then from third law floor also exerts force F on box in upward direction <img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/45ce83c7e3a0c50f98f61b7a5e7787dd-.png" /> F -Mg = Ma ⇒ (7 Mg/4)-Mg=Ma ⇒ a=(3g/4)

Q. With what acceleration ‘a’ should the box of figure moving up so that the block of mass $M$ exerts a force $7 M g /4$ on the floor of the box?

$g /4$

$g /2$

$3 g /4$

$4 g$

$FB D$ of $M$ : If $M$ exerts force $F = 7 M g /4$ on floor, then from third law floor also exerts force $F$ on box in upward direction

$F - M g = M a$

$\Rightarrow \frac{7 M g}{4} - M g = M a$

$\Rightarrow a = \frac{3 g}{4}$

Q. With what acceleration ‘a’ should the box of figure moving up so that the block of mass M exerts a force 7Mg/4 on the floor of the box?

g/4

g/2

3g/4

4g