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A body of mass \(m_{1}\) moving with certain velocity collides elastically with another body of mass \(m_{2}\) at rest. The perecntage kinctic cnergy transferred by \(m_{1}\) to \(m_{2}\) in the following cases Column-I (a) \(m_{2}=m_{1}\) (b) \(m_{2}=4 m_{1}\) (c) \(m_{2}=3 m_{1}\) (d) \(m_{2}=9 m_{1}\) Column-II (p) \(64 \%\) (q) \(36 \%\) (r) \(100 \%\) (s) \(75 \%\)

Short Answer

Expert verified
(a) 100%, (b) 64%, (c) 75%, (d) 36%

Step by step solution

01

Understanding the Problem

We need to find the percentage of kinetic energy transferred from a body of mass \(m_1\) to a body of mass \(m_2\) in an elastic collision for different mass ratios. An elastic collision conserves both momentum and kinetic energy. The percentage of kinetic energy transferred depends on the mass ratio \(m_2/m_1\).
02

Percentage Energy Transfer Formula

The formula for the percentage of kinetic energy transferred from \(m_1\) to \(m_2\) is \( \left( \frac{4m_1 m_2}{(m_1 + m_2)^2} \right) \times 100\%.\) Using this formula, we can calculate the percentage for each given scenario.
03

Case (a): \(m_2 = m_1\)

Substitute \(m_2 = m_1\) into the formula: \(\left( \frac{4m_1^2}{(m_1 + m_1)^2} \right) \times 100\% = \left( \frac{4m_1^2}{4m_1^2} \right) \times 100\% = 100\%.\)So, in this case, the kinetic energy transfer is \(100\%\).
04

Case (b): \(m_2 = 4m_1\)

Substitute \(m_2 = 4m_1\) into the formula: \(\left( \frac{4m_1 \times 4m_1}{(m_1 + 4m_1)^2} \right) \times 100\% = \left( \frac{16m_1^2}{25m_1^2} \right) \times 100\% = 64\%\). The percentage of kinetic energy transferred is \(64\%\).
05

Case (c): \(m_2 = 3m_1\)

Substitute \(m_2 = 3m_1\) into the formula: \(\left( \frac{4m_1 \times 3m_1}{(m_1 + 3m_1)^2} \right) \times 100\% = \left( \frac{12m_1^2}{16m_1^2} \right) \times 100\% = 75\%\).The percentage of kinetic energy transferred is \(75\%\).
06

Case (d): \(m_2 = 9m_1\)

Substitute \(m_2 = 9m_1\) into the formula: \(\left( \frac{4m_1 \times 9m_1}{(m_1 + 9m_1)^2} \right) \times 100\% = \left( \frac{36m_1^2}{100m_1^2} \right) \times 100\% = 36\%\).The percentage of kinetic energy transferred is \(36\%\).
07

Matching Cases with Percentages

Now, match the calculated percentages to their respective options in Column-II:- (a) \(m_2 = m_1\): \(100\%\) corresponds to \(\text{(r)}\).- (b) \(m_2 = 4m_1\): \(64\%\) corresponds to \(\text{(p)}\).- (c) \(m_2 = 3m_1\): \(75\%\) corresponds to \(\text{(s)}\).- (d) \(m_2 = 9m_1\): \(36\%\) corresponds to \(\text{(q)}\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Kinetic Energy Transfer
Kinetic energy transfer is a fundamental concept when studying elastic collisions. In these interactions, two objects collide, and energy is transferred between them.
For elastic collisions, both kinetic energy and momentum are conserved, meaning they remain constant before and after the collision.
A common formula used to calculate the percentage of kinetic energy transferred from one object to another is given by: \[\left( \frac{4m_1 m_2}{(m_1 + m_2)^2} \right) \times 100\%\] where \( m_1 \) and \( m_2 \) represent the masses of the two objects involved.
This formula allows us to determine what fraction of the initial kinetic energy is transferred from \( m_1 \) to \( m_2 \).
  • When \( m_1 \) and \( m_2 \) are equal, the formula results in a 100% energy transfer.
  • If \( m_2 \) is significantly larger than \( m_1 \), a smaller percentage of energy is transferred.
Thus, the mass ratio plays a crucial role in determining how energy is shared during the collision.
Conservation of Momentum
The conservation of momentum is a cornerstone principle in physics, especially evident in collision dynamics. This concept indicates that the total momentum of a system remains constant if no external forces act on it.
In the context of an elastic collision between two bodies, the momentum is exchanged but conserved. Mathematically, this is expressed as:\[m_1v_{1_i} + m_2v_{2_i} = m_1v_{1_f} + m_2v_{2_f}\]where:
  • \(v_{1_i}\) and \(v_{2_i}\) are the initial velocities of \(m_1\) and \(m_2\) respectively.
  • \(v_{1_f}\) and \(v_{2_f}\) are their final velocities.
This principle ensures that any change in the momentum of one object is countered by an equivalent and opposite change in the momentum of the other object, a key factor influencing their post-collision velocities.
The conservation of momentum, combined with the conservation of kinetic energy, defines how energy is redistributed during the collision.
Mass Ratio
The mass ratio between colliding objects plays a pivotal role in the dynamics of an elastic collision. It is expressed as \( \frac{m_2}{m_1} \).
This ratio impacts both the results of energy transfer and the movement post-collision.
  • When \( m_2 \) equals \( m_1 \), energy transfer efficiency reaches its maximum, resulting in a full 100% transfer.
  • For \( m_2 = 4m_1 \), a significant transfer still occurs but only at 64%.
Larger mass ratios (where \( m_2 \) is much greater than \( m_1 \)) translate to more energy being retained by the moving mass \( m_1 \). Conversely, when \( m_2 \) is smaller, more energy is transferred to it.
Understanding mass ratio implications aids in predicting the outcome of elastic collisions in various systems, from billiard balls colliding to particles in a physics experiment.
Collision Dynamics
Collision dynamics describe how objects interact when they collide, taking into account their velocities, masses, and the type of collision. In the case of elastic collisions, both momentum and kinetic energy are conserved, making calculations straightforward.
The dynamics depend on several factors:
  • The initial velocity of each object: Determines the post-collision velocity changes.
  • The mass of each object: Influences how momentum and energy are distributed.
The result of the collision can be accurately predicted using the formulas for kinetic energy transfer and momentum conservation.
For example, if two objects of equal mass collide head-on, they exchange their velocities. This is a direct outcome of the conservation rules governing their interaction.
Studying these dynamics equips you to foresee how real-world systems behave during impacts, an essential skill in both theoretical and applied physics.

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