ï»¿ A body mass 1 kg is thrown upwards with velocity 20 ms-1. It momentarily comes to rest after attaining a height of 18 m. How much energy is lost due to air friction? Â (g = 10 ms-2) from Physics Gravitation Class 11 Manipur Board

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A body mass 1 kg is thrown upwards with velocity 20 ms-1. It momentarily comes to rest after attaining a height of 18 m. How much energy is lost due to air friction? Â (g = 10 ms-2)

• 20 J

• 30 J

• 40 J

• 10 J

A.

20 J

The energy lost due to air friction is equal to the difference of initial kinetic energy and final potential energy.

Initially, body possess only kinetic energy and after attaining a height the kinetic energy is zero.

Therefore, loss of energy = KE - PE

=

The energy lost due to air friction is equal to the difference of initial kinetic energy and final potential energy.

Initially, body possess only kinetic energy and after attaining a height the kinetic energy is zero.

Therefore, loss of energy = KE - PE

=

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The position co-ordinates of two particles of masses m1Â and m2are (x1, y1, z1) and (x2, y2, z2) respectively. Find the coordinates of the centre of mass.

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Comparing the coefficients of Â , we get

Â

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