You visited us 1 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard XII

Physics

Maximum Push Using Friction

A time depend...

Question

A time dependent force $F = 3 t$ ( $F$ in Newtons and $t$ in seconds) acts on three blocks $m_{1}, m_{2}$ and $m_{3}$ kept in contact on a rough ground as shown. Coefficient of friction between blocks and ground is $0.4$ . If $m_{1}, m_{2}$ and $m_{3}$ are $3 k g, 2 k g$ and $1 k g$ respectively, the time after which the blocks start to move is $(g = 10 m s^{- 2})$

4 s e c

No worries! We‘ve got your back. Try BYJU‘S free classes today!

8 s e c

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

\frac{8}{3} s e c

No worries! We‘ve got your back. Try BYJU‘S free classes today!

\frac{4}{3} s e c

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is B $8 s e c$

Taking the blocks as one system.
Friction force on the system, $f = μ (m_{1} + m_{2} + m_{3}) g = 0.4 (3 + 2 + 1) \times 10 = 24 N$

To move the blocks,
$F \geq f \Rightarrow 3 t \geq 24, \Rightarrow t \geq 8 s$

Suggest Corrections

Similar questions

Q. Three blocks

m_{1}, m_{2}

and

m_{3}

of masses

8 kg, 3 kg

and

1 kg

are placed in contact on a smooth surface. Forces

F_{1} = 140 N

and

F_{2} = 20 N

are acting on blocks

m_{1}

and

m_{3}

respectively as shown. The reaction between blocks

m_{2}

and

m_{3}

Q. Three blocks

m_{1}, m_{2}

and

m_{3}

of masses

8 kg, 3 kg

and

1 kg

are placed in contact on a smooth surface. Forces

F_{1} = 140 N

and

F_{2} = 20 N

are acting on blocks

m_{1}

and

m_{3}

respectively as shown. The reaction between blocks

m_{2}

and

m_{3}

Three blocks of mass $M_{1}$ , $M_{2}$ & $M_{3}$ are connected by massless strings as shown on a frictionless table. Where $T_{1}$ is the tension in the string between block $M_{1}$ and $M_{2}$ , $T_{2}$ is the tension in the string between block $M_{2}$ and $M_{3}$ . They're pulled with a force $F = 40 N$ . If $M_{1}$ =10 kg, $M_{2}$ = 6 kg and $M_{3}$ = 4 kg, then tension $T_{2}$ will be: