A uniform cube of side a and mass m rests on a rough horizontal table. A horizontal force F is applied normal to one of the faces at a point that is directly above the centre of the face, at a height 3 a / 4 above the

BITSAT 2009

Exam: BITSAT
Year: 2009
Subject: Physics
Chapter: Rotational Motion

BITSAT 2009 · Physics · Rotational Motion

A uniform cube of side a and mass m rests on a rough horizontal...

A uniform cube of side a and mass m rests on a rough horizontal table. A horizontal force

\mathrm{F}

is applied normal to one of the faces at a point that is directly above the centre of the face, at a height

3 \mathrm{a} / 4

above the base. The minimum value of

\mathrm{F}

for which the cube begins to topple an edge is (assume that cube does not slide) A uniform cube of side a and mass m rests on a rough horizontal table. A horizontal force F is applied normal to one of

A uniform cube of side a and mass m rests on a rough horizontal table. A horizontal force F is applied normal to one of

Options

A $\frac{\mathrm{mg}}{3}$
B $\frac{\mathrm{mg}}{2}$
C $\frac{2 \mathrm{mg}}{3}$
D $\frac{3 \mathrm{mg}}{4}$

Correct answer

C. $\frac{2 \mathrm{mg}}{3}$

Step-by-step solution

For toppling about edge

x

x At the moment of toppling the normal force pass through axis

\mathrm{xx}

\mathrm{F}_{\min } \frac{3 \mathrm{a}}{4}=\mathrm{mg} \frac{\mathrm{a}}{2} \text{ or } \mathrm{F}_{\min }=\frac{2 \mathrm{mg}}{3}

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