Question

True oe false:

1) S.I unit of position vector of centre of mass is 'metre (m)'.

2) Linear momentum of a body is a vector quantity.

3) Cross product of two vectors is not commutative.

4) The escape velocity of a particle depends on its mass.

5) The magnitude of force of limiting friction (F) is inversely proportional to a normal reaction.

Please give me correct answer if you give me wrong answer I will report your account.......⚠️​

Answer 1

Answer- The above questions are from the chapters 'Kinematics', 'Dynamics', 'System of Particles and Rotational Motion' and 'Gravitation'.

Given question: True or false:

1) S.I. unit of position vector of centre of mass is 'metre (m)'.

2) Linear momentum of a body is a vector quantity.

3) Cross product of two vectors is not commutative.

4) The escape velocity of a particle depends on its mass.

5) The magnitude of force of limiting friction (F) is inversely proportional to a normal reaction.

Answer:

1) True

⇒ Position vector of centre of mass determines its position. So, its S.I. unit is metre.

2) True

⇒ Linear Momentum ($\vec{p}$) = mass (m) × velocity ($\vec{v}$)

As velocity of a body is a vector quantity, so linear momentum is also a vector quantity.

3) True

⇒ Cross product of two vectors is not commutative i.e.

$\vec{A} \times (\vec{B} \times \vec{C}) \neq (\vec{A} \times \vec{B}) \times \vec{C}$

4) False

⇒ Escape velocity of a particle $(v_e) = \sqrt{2gR_e}$

As there is no mass in the formula above, so escape velocity is not dependent upon mass.

5) False

⇒ F = μN, where F = magnitude of force of limiting friction, μ = coefficient of friction and N = Normal force.

Clearly, $F \propto N$ i.e. directly proportional.

Answer 2

Answer:

1- true

2-true

3-true

4-false

5-false.