#### Famous palaeonotologist/Palaeobotanist of India was:

- P.Maheshwari
- B.P. Pal
- S. R. Kashyap
- B.Sahni

#### Answer:The correct answer is: B.Sahni

## Book A Free Demo

Grade*

### Related Questions to study

#### A disc is rolling (without slipping) on a horizontal surface is its centre and and are two points equidistant from . Let , and be the magnitude of velocities of pints and respectively, then

Velocity of any point on the disc, ,

where is distance of point from .

#### A disc is rolling (without slipping) on a horizontal surface is its centre and and are two points equidistant from . Let , and be the magnitude of velocities of pints and respectively, then

Velocity of any point on the disc, ,

where is distance of point from .

#### A small object of uniform density roll up a curved surface with an initial velocity . If reaches up to a maximum height of with respect to the initial position. The object is

Body is disc.

#### A small object of uniform density roll up a curved surface with an initial velocity . If reaches up to a maximum height of with respect to the initial position. The object is

Body is disc.

#### A uniform rod of length and mass is free to rotate about point . The rod is released from rest in the horizontal position. Given that the moment of inertia of the rod about is, the initial angular acceleration of the rod will be

Where is mass of rod and is length.

Torque acting on centre of gravity of rod is given by

or

or

or

#### A uniform rod of length and mass is free to rotate about point . The rod is released from rest in the horizontal position. Given that the moment of inertia of the rod about is, the initial angular acceleration of the rod will be

Where is mass of rod and is length.

Torque acting on centre of gravity of rod is given by

or

or

or

#### If then descending order of

is

#### If then descending order of

is

#### Three rods of the same mass are placed as shown in figure. What will be the coordinates of centre of mass of the system?

#### Three rods of the same mass are placed as shown in figure. What will be the coordinates of centre of mass of the system?

#### Two blocks and are connected by a massless string (shown in figure). A force of 30 N is applied on block . The distance travelled by centre of mass in 2 s starting from rest is

m

#### Two blocks and are connected by a massless string (shown in figure). A force of 30 N is applied on block . The distance travelled by centre of mass in 2 s starting from rest is

m

#### Find the velocity of centre of the system shown in the figure.

kg,

#### Find the velocity of centre of the system shown in the figure.

kg,

#### The blocks and , each of mass , are connected by massless spring of natural length and spring constant . The blocks are initially resting on a smooth horizontal floor with the spring at its natural length, as shown in figure. A third identical block , also of mass , moves on the floor with a speed along the line joining and , and collides with . Then

kinetic energy of system at that stage

Further loss in KE> = gain in elastic potential energy

,

#### The blocks and , each of mass , are connected by massless spring of natural length and spring constant . The blocks are initially resting on a smooth horizontal floor with the spring at its natural length, as shown in figure. A third identical block , also of mass , moves on the floor with a speed along the line joining and , and collides with . Then

kinetic energy of system at that stage

Further loss in KE> = gain in elastic potential energy

,

#### A set of identical cubical blocks lies at rest parallel to each other along a line on a smooth horizontal surface. The separation between the near surfaces of any two adjacent blocks is . The block at one end is given a speed towards the next one at time . All collision are completely elastic. Then

Since collision is 100% elastic, now first block comes to rest and 2nd block starts moving towards the 3rd block with a velocity and takes time to reach 3rd block and so on

Total time time

Finally only the last th block is in motion velocity , hence final velocity of centre of mass

#### A set of identical cubical blocks lies at rest parallel to each other along a line on a smooth horizontal surface. The separation between the near surfaces of any two adjacent blocks is . The block at one end is given a speed towards the next one at time . All collision are completely elastic. Then

Since collision is 100% elastic, now first block comes to rest and 2nd block starts moving towards the 3rd block with a velocity and takes time to reach 3rd block and so on

Total time time

Finally only the last th block is in motion velocity , hence final velocity of centre of mass

#### Which of the following noble gas was reacted with by Bartlett to prepare the first noble gas compounds -

#### Which of the following noble gas was reacted with by Bartlett to prepare the first noble gas compounds -

#### In the given figure, two bodies of mass and are connected by massless spring of force constant and are placed on a smooth surface (shown in figure), then

#### In the given figure, two bodies of mass and are connected by massless spring of force constant and are placed on a smooth surface (shown in figure), then

#### Two blocks and () are connected with a spring of force constant and are inclined at a angel with horizontal. If the system is released from rest, which one of the following statements is/are correct?

#### Two blocks and () are connected with a spring of force constant and are inclined at a angel with horizontal. If the system is released from rest, which one of the following statements is/are correct?

#### Two negatively charges particles having charges and and masses and respectively are projected one after another into a region with equal initial velocity. The electric field is along the -axis, while the direction of projection makes an angle a with the -axis. If the ranges of the two particles along the -axis are equal then one can conclude that

It means, for both particles are same

This is possible when

and

#### Two negatively charges particles having charges and and masses and respectively are projected one after another into a region with equal initial velocity. The electric field is along the -axis, while the direction of projection makes an angle a with the -axis. If the ranges of the two particles along the -axis are equal then one can conclude that

It means, for both particles are same

This is possible when

and

#### A particle of mass moves in the plane with a velocity along the straight line . If the angular momentum of the particle with respect to origin is when it is at and when it is at , then

Therefore, the magnitude of is

where is the distance of closest approach of the particle to the origin. As is same for both the particles, hence .

#### A particle of mass moves in the plane with a velocity along the straight line . If the angular momentum of the particle with respect to origin is when it is at and when it is at , then

Therefore, the magnitude of is

where is the distance of closest approach of the particle to the origin. As is same for both the particles, hence .

In the given figure four identical spheres of equal mass are suspended by wires of equal length , so that all spheres are almost touching to each other. If the sphere 1 is released from the horizontal position and all collisions are elastic, the velocity of sphere 4 just after collision is

Or

Or

Since, all collisions are elastic, so velocity of sphere 1 is transferred to sphere 2, then from 2 to 3 and finally from 3 to 4. Hence, just after collision, the sphere 4 attains a velocity equal to

In the given figure four identical spheres of equal mass are suspended by wires of equal length , so that all spheres are almost touching to each other. If the sphere 1 is released from the horizontal position and all collisions are elastic, the velocity of sphere 4 just after collision is

Or

Or

Since, all collisions are elastic, so velocity of sphere 1 is transferred to sphere 2, then from 2 to 3 and finally from 3 to 4. Hence, just after collision, the sphere 4 attains a velocity equal to