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PHXI05:LAWS OF MOTION

363377 Assertion :
Use of ball bearings between two moving parts of machine is a common practice.
Reason :
Ball bearings reduce vibrations and provide good stability.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXI05:LAWS OF MOTION

363378 Assertion :
A horse has to pull a cart harder during the first few steps of his motion.
Reason :
Dynamic friction is larger than limiting friction.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXI05:LAWS OF MOTION

363379 A body of mass $2 k g$ is placed on a rough horizontal plane. The coefficient of friction between the body and the plane is 0.2 .Then,

1 body will move in forward direction, if

F = 5 N

.

2 body will move in backward direction with an acceleration

0.6 m s^{- 2},

if force

F = 3 N .

3 body will be in rest condition, if

F = 3 N

.

4 Both (1) and (3) are correct.

Explanation:

For moving the body, applied force should
be greater than or equal to limiting friction,
(i.e. $μ N$ ). The limiting friction is
$f_{2} = μ N = μ m g$
$= 0.2 \times 2 \times 9.8 = 3.92 N$
(1) Since, applied force $F = 5 N$ , so body starts
to move in forward direction.
(2) Here, applied force is lesser than limiting
friction. So, body does not move.
(3) Body will not move as $F < F_{s}$ . Hence,
option (4) is correct.

PHXI05:LAWS OF MOTION

363380 Assertion :
It is difficult to move a cycle along the road with its brakes on.
Reason :
Sliding friction is greater than roling friction.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXI05:LAWS OF MOTION

363381 The situation shown in the figure, all strings and pulleys are ideal. If tension in the string connecting blocks $A$ and $C$ is $\frac{1350}{11 n} N$ . Find the value of $n$
supporting img

1 1

2 3

3 5

4 9

Explanation:

Equation of motion for block $C$ is
$m_{C} g - T = m_{C} a_{C}$
Or $180 - T = 18 a_{C} (1)$
$T - 45 = 9 a_{A} (2)$
and $2 T - 45 = 9 a_{B} = 9 (\frac{a_{C} - a_{A}}{2}) (3)$
or $4 T - 90 = 9 a_{C} - 9 a_{A}$
or $4 T - 90 = 9 (\frac{180 - T}{18}) - 9 (\frac{T - 45}{9})$
$4 T + \frac{T}{2} + T = 90 + 45 = 135$
$∴ T = \frac{135}{5.5} = \frac{1350}{55} = \frac{1350}{11 n}$
Comparing with the given value, we have $n = 5$

PHXI05:LAWS OF MOTION

363377 Assertion :
Use of ball bearings between two moving parts of machine is a common practice.
Reason :
Ball bearings reduce vibrations and provide good stability.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXI05:LAWS OF MOTION

363378 Assertion :
A horse has to pull a cart harder during the first few steps of his motion.
Reason :
Dynamic friction is larger than limiting friction.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXI05:LAWS OF MOTION

363379 A body of mass $2 k g$ is placed on a rough horizontal plane. The coefficient of friction between the body and the plane is 0.2 .Then,

1 body will move in forward direction, if

F = 5 N

.

2 body will move in backward direction with an acceleration

0.6 m s^{- 2},

if force

F = 3 N .

3 body will be in rest condition, if

F = 3 N

.

4 Both (1) and (3) are correct.

Explanation:

For moving the body, applied force should
be greater than or equal to limiting friction,
(i.e. $μ N$ ). The limiting friction is
$f_{2} = μ N = μ m g$
$= 0.2 \times 2 \times 9.8 = 3.92 N$
(1) Since, applied force $F = 5 N$ , so body starts
to move in forward direction.
(2) Here, applied force is lesser than limiting
friction. So, body does not move.
(3) Body will not move as $F < F_{s}$ . Hence,
option (4) is correct.

PHXI05:LAWS OF MOTION

363380 Assertion :
It is difficult to move a cycle along the road with its brakes on.
Reason :
Sliding friction is greater than roling friction.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXI05:LAWS OF MOTION

363381 The situation shown in the figure, all strings and pulleys are ideal. If tension in the string connecting blocks $A$ and $C$ is $\frac{1350}{11 n} N$ . Find the value of $n$
supporting img

1 1

2 3

3 5

4 9

Explanation:

Equation of motion for block $C$ is
$m_{C} g - T = m_{C} a_{C}$
Or $180 - T = 18 a_{C} (1)$
$T - 45 = 9 a_{A} (2)$
and $2 T - 45 = 9 a_{B} = 9 (\frac{a_{C} - a_{A}}{2}) (3)$
or $4 T - 90 = 9 a_{C} - 9 a_{A}$
or $4 T - 90 = 9 (\frac{180 - T}{18}) - 9 (\frac{T - 45}{9})$
$4 T + \frac{T}{2} + T = 90 + 45 = 135$
$∴ T = \frac{135}{5.5} = \frac{1350}{55} = \frac{1350}{11 n}$
Comparing with the given value, we have $n = 5$

PHXI05:LAWS OF MOTION

363377 Assertion :
Use of ball bearings between two moving parts of machine is a common practice.
Reason :
Ball bearings reduce vibrations and provide good stability.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXI05:LAWS OF MOTION

363378 Assertion :
A horse has to pull a cart harder during the first few steps of his motion.
Reason :
Dynamic friction is larger than limiting friction.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXI05:LAWS OF MOTION

363379 A body of mass $2 k g$ is placed on a rough horizontal plane. The coefficient of friction between the body and the plane is 0.2 .Then,

1 body will move in forward direction, if

F = 5 N

.

2 body will move in backward direction with an acceleration

0.6 m s^{- 2},

if force

F = 3 N .

3 body will be in rest condition, if

F = 3 N

.

4 Both (1) and (3) are correct.

Explanation:

For moving the body, applied force should
be greater than or equal to limiting friction,
(i.e. $μ N$ ). The limiting friction is
$f_{2} = μ N = μ m g$
$= 0.2 \times 2 \times 9.8 = 3.92 N$
(1) Since, applied force $F = 5 N$ , so body starts
to move in forward direction.
(2) Here, applied force is lesser than limiting
friction. So, body does not move.
(3) Body will not move as $F < F_{s}$ . Hence,
option (4) is correct.

PHXI05:LAWS OF MOTION

363380 Assertion :
It is difficult to move a cycle along the road with its brakes on.
Reason :
Sliding friction is greater than roling friction.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXI05:LAWS OF MOTION

363381 The situation shown in the figure, all strings and pulleys are ideal. If tension in the string connecting blocks $A$ and $C$ is $\frac{1350}{11 n} N$ . Find the value of $n$
supporting img

1 1

2 3

3 5

4 9

Explanation:

Equation of motion for block $C$ is
$m_{C} g - T = m_{C} a_{C}$
Or $180 - T = 18 a_{C} (1)$
$T - 45 = 9 a_{A} (2)$
and $2 T - 45 = 9 a_{B} = 9 (\frac{a_{C} - a_{A}}{2}) (3)$
or $4 T - 90 = 9 a_{C} - 9 a_{A}$
or $4 T - 90 = 9 (\frac{180 - T}{18}) - 9 (\frac{T - 45}{9})$
$4 T + \frac{T}{2} + T = 90 + 45 = 135$
$∴ T = \frac{135}{5.5} = \frac{1350}{55} = \frac{1350}{11 n}$
Comparing with the given value, we have $n = 5$

PHXI05:LAWS OF MOTION

363377 Assertion :
Use of ball bearings between two moving parts of machine is a common practice.
Reason :
Ball bearings reduce vibrations and provide good stability.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXI05:LAWS OF MOTION

363378 Assertion :
A horse has to pull a cart harder during the first few steps of his motion.
Reason :
Dynamic friction is larger than limiting friction.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXI05:LAWS OF MOTION

363379 A body of mass $2 k g$ is placed on a rough horizontal plane. The coefficient of friction between the body and the plane is 0.2 .Then,

1 body will move in forward direction, if

F = 5 N

.

2 body will move in backward direction with an acceleration

0.6 m s^{- 2},

if force

F = 3 N .

3 body will be in rest condition, if

F = 3 N

.

4 Both (1) and (3) are correct.

Explanation:

For moving the body, applied force should
be greater than or equal to limiting friction,
(i.e. $μ N$ ). The limiting friction is
$f_{2} = μ N = μ m g$
$= 0.2 \times 2 \times 9.8 = 3.92 N$
(1) Since, applied force $F = 5 N$ , so body starts
to move in forward direction.
(2) Here, applied force is lesser than limiting
friction. So, body does not move.
(3) Body will not move as $F < F_{s}$ . Hence,
option (4) is correct.

PHXI05:LAWS OF MOTION

363380 Assertion :
It is difficult to move a cycle along the road with its brakes on.
Reason :
Sliding friction is greater than roling friction.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXI05:LAWS OF MOTION

363381 The situation shown in the figure, all strings and pulleys are ideal. If tension in the string connecting blocks $A$ and $C$ is $\frac{1350}{11 n} N$ . Find the value of $n$
supporting img

1 1

2 3

3 5

4 9

Explanation:

Equation of motion for block $C$ is
$m_{C} g - T = m_{C} a_{C}$
Or $180 - T = 18 a_{C} (1)$
$T - 45 = 9 a_{A} (2)$
and $2 T - 45 = 9 a_{B} = 9 (\frac{a_{C} - a_{A}}{2}) (3)$
or $4 T - 90 = 9 a_{C} - 9 a_{A}$
or $4 T - 90 = 9 (\frac{180 - T}{18}) - 9 (\frac{T - 45}{9})$
$4 T + \frac{T}{2} + T = 90 + 45 = 135$
$∴ T = \frac{135}{5.5} = \frac{1350}{55} = \frac{1350}{11 n}$
Comparing with the given value, we have $n = 5$

PHXI05:LAWS OF MOTION

363377 Assertion :
Use of ball bearings between two moving parts of machine is a common practice.
Reason :
Ball bearings reduce vibrations and provide good stability.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXI05:LAWS OF MOTION

363378 Assertion :
A horse has to pull a cart harder during the first few steps of his motion.
Reason :
Dynamic friction is larger than limiting friction.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXI05:LAWS OF MOTION

363379 A body of mass $2 k g$ is placed on a rough horizontal plane. The coefficient of friction between the body and the plane is 0.2 .Then,

1 body will move in forward direction, if

F = 5 N

.

2 body will move in backward direction with an acceleration

0.6 m s^{- 2},

if force

F = 3 N .

3 body will be in rest condition, if

F = 3 N

.

4 Both (1) and (3) are correct.

Explanation:

For moving the body, applied force should
be greater than or equal to limiting friction,
(i.e. $μ N$ ). The limiting friction is
$f_{2} = μ N = μ m g$
$= 0.2 \times 2 \times 9.8 = 3.92 N$
(1) Since, applied force $F = 5 N$ , so body starts
to move in forward direction.
(2) Here, applied force is lesser than limiting
friction. So, body does not move.
(3) Body will not move as $F < F_{s}$ . Hence,
option (4) is correct.

PHXI05:LAWS OF MOTION

363380 Assertion :
It is difficult to move a cycle along the road with its brakes on.
Reason :
Sliding friction is greater than roling friction.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXI05:LAWS OF MOTION

363381 The situation shown in the figure, all strings and pulleys are ideal. If tension in the string connecting blocks $A$ and $C$ is $\frac{1350}{11 n} N$ . Find the value of $n$
supporting img

1 1

2 3

3 5

4 9

Explanation:

Equation of motion for block $C$ is
$m_{C} g - T = m_{C} a_{C}$
Or $180 - T = 18 a_{C} (1)$
$T - 45 = 9 a_{A} (2)$
and $2 T - 45 = 9 a_{B} = 9 (\frac{a_{C} - a_{A}}{2}) (3)$
or $4 T - 90 = 9 a_{C} - 9 a_{A}$
or $4 T - 90 = 9 (\frac{180 - T}{18}) - 9 (\frac{T - 45}{9})$
$4 T + \frac{T}{2} + T = 90 + 45 = 135$
$∴ T = \frac{135}{5.5} = \frac{1350}{55} = \frac{1350}{11 n}$
Comparing with the given value, we have $n = 5$