Tag: mechanics

Questions Related to mechanics

 A ball of mass 3 kg moving with a velocity of 4 m/s undergoes a perfectly- elastic collision with a stationary ball of mass m. After the impact is over, the kinetic energy of the 3 kg ball is 6 J. The possible value of m is/are :

collisions in one dimension collisions work, energy and power mechanics physics

  1. 1 kg only

  2. 1 kg , 9kg

  3. 1 kg, 6kg

  4. 6kg only

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Correct Option: A

A proton of mass $m _p$ collides with a heavy particle. After collision proton bunches back with 4/9 of its intial kinetic energy. Collision is perfectly elastic. Find mass of heavy particle.

collisions in one dimension collisions work, energy and power mechanics physics

  1. 5 $m _p$

  2. 6 $m _p$

  3. 3 $m _p$

  4. 1.5 $m _p$

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Correct Option: C

In an elastic collision the K.E of one body decreases by $100 J$. If the masses colliding bodies are in the ratio 3:4 the K.E of the other body increase by 

collisions in one dimension collisions work, energy and power mechanics physics

  1. $\dfrac{400}{3} J$

  2. $\dfrac{500}{3} J$

  3. $100 J$

  4. $0$

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Correct Option: A

Two identical balls  $A$  and  $B$  having velocities of  $0.5\mathrm { m } / \mathrm { s }$  and  $- 0.3 \mathrm { m } / \mathrm { s }$  respectively collide elastically in one dimension. The velocities of  $B$  and  $\mathrm { A }$  after the collision respectively will be

collisions in one dimension collisions work, energy and power mechanics physics

  1. $0.3 \mathrm { m } / \mathrm { s } \text { and } 0.5 \mathrm { m } / \mathrm { s }$

  2. $- 0.5 \mathrm { m } / \mathrm { s } \text { and } 0.3 \mathrm { m } / \mathrm { s }$

  3. $0.5 \mathrm { m } / \mathrm { s } \text { and } - 0.3 \mathrm { m } / \mathrm { s }$

  4. $- 0.3 \mathrm { m } / \mathrm { s } \text { and } 0.5 \mathrm { m } / \mathrm { s }$

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Correct Option: C

A particle of mass $ m _1 $ hits another particle of mass $ m _2 $ at rest with a velocity $ \overrightarrow { u }  $. The collision is head-on and elastic.If $ m _1 >> m _2 $, then after collision, the velocity of $ m _2 $ will be-

collisions in one dimension collisions work, energy and power mechanics physics

  1. $ \overrightarrow { u } $

  2. $ - \overrightarrow { u } $

  3. $ 2 \overrightarrow { u } $

  4. $ -2 \overrightarrow { u } $

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Correct Option: C

Which of the following does no undergo elastic collision?

collisions in one dimension collisions work, energy and power mechanics physics

  1. When $ m _1 = m _2$ and $m _2 $ is stationary,there is maximum transfer of kinetic energy in head an collision

  2. When $ m _1 = m _2 $ is stationary,there is minimum transfer of momentum in head on collision

  3. When $ m _1 >> m _2 $ is stationary,after head on collision $ m _2 $ moves with twice the velocity of $ m _1 $

  4. When the collision is oblique and $ m _1 = m _2 with m _2 $ stationary,after the collision the particle move in opposite directions.

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Correct Option: A

A perfectly elastic ball falls on a horizontal floor from a height in a time $t$. It will hit the floor again after a time $t'$. The ratio of $t'$ and t is 

collisions in one dimension collisions work, energy and power mechanics physics

  1. $1:1$

  2. $1:2$

  3. $2:1$

  4. $1:4$

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Correct Option: B

IN a collision between two solid spheres, velocity of separation along the external forces act on the system of two sphers during impact 

collisions in one dimension collisions work, energy and power mechanics physics

  1. cannot be greater then velocity of approach

  2. cannot be less then velocity of approach

  3. cannot be equal to velocity of approach

  4. none of these

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Correct Option: C

A sphere P of mass m and  velocity $\underset{V _{1}}{\rightarrow}$  undergoes an oblique and perfectly elastic collision with an identical sphere Q initially at rest.  The  angle $\Theta $  between the velocites of the spheres after the collision shall be

collisions in one dimension collisions work, energy and power mechanics physics

  1. 0

  2. $45^{\circ}$

  3. $90^{\circ}$

  4. $180^{\circ}$

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Correct Option: C

A neutron collides head-on with a stationary hydrogen atom $( _1H^1)$ in ground state, then choose the correct statement (assume that mass of neutron and mass of $( _1H^1)$ atom is same)

collisions in one dimension collisions work, energy and power mechanics physics

  1. If kinetic energy of the neutron is less than $13.6eV$, collision must be elastic

  2. If kinetic energy of the neutron is less than $13.6eV$, collision must be inelastic

  3. Inelastic collision may take place only when initial kinetic energy of neutron is greater than $13.6eV$

  4. Perfectly inelastic collisin cannot take place.

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Correct Option: A