MCQ

MCQ 1011 Mark

A body $B$ lies on a smooth horizontal table and another body $A$ is placed on $B$. The coefficient of friction between$A$ and $B$ is $\mu$. What acceleration given to $B$ will cause slipping to occur between $A$ and $B$

✓
$\mu g$
B
$g / \mu$
C
$\mu / g$
D
$\sqrt{\mu g}$

Answer

Correct option: A.

$\mu g$

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MCQ 1021 Mark

A block of mass $5 \mathrm{~kg}$ is on a rough horizontal surface and is at rest. Now a force of $24 N$ is imparted to it with negligible impulse. If the coefficient of kinetic friction is 0.4 and $g=9.8 \mathrm{~m} / \mathrm{s}^2$, then the acceleration of the block is

A
$0.26 \mathrm{~m} / \mathrm{s}^2$
B
$0.39 \mathrm{~m} / \mathrm{s}^2$
C
$0.69 \mathrm{~m} / \mathrm{s}^2$
✓
$0.88 \mathrm{~m} / \mathrm{s}^2$

Answer

Correct option: D.

$0.88 \mathrm{~m} / \mathrm{s}^2$

(d) Net force $=$ Applied force - Friction force
$m a=24-\mu m g$
$=24-0.4 \times 5 \times 9.8$
$=24-19.6 $
$ \Rightarrow a=\frac{4.4}{5}=0.88\ m / s^2$

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MCQ 1031 Mark

Which one of the following statements is correct

A
Rolling friction is greater than sliding friction
✓
Rolling friction is less than sliding friction
C
Rolling friction is equal to sliding friction
D
Rolling friction and sliding friction are same

Answer

Correct option: B.

Rolling friction is less than sliding friction

(b)

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JEE physics MCQ