Question

Two objects each of mass \[2\,kg\] all moving in the same straight line but opposite directions. The velocity of each object is \[2.5\,m/s\] before the collision during which they stick together. What will the velocity of the combined object be after the collision?
A. \[2\,m/s\]
B. \[6\,m/s\]
C. \[0\] (zero)
D. \[6.8\,m/s\]

Answer 1

Hint:A collision is defined in physics as any event in which two or more bodies exert forces on each other in a relatively short period. Although the most common application of the term collusion refers to incidents in which two or more objects collide with great force, the scientific application of the term implies nothing about the magnitude of the force.

Complete step by step answer:
Collision is a short-duration interaction between two or more bodies that causes a change in motion of the bodies involved due to internal forces acting between them. Collisions involve the application of forces (there is a change in velocity). The closing speed is the magnitude of the velocity difference just before impact.

Every collision and momentum. The conservation of kinetic energy is what distinguishes different types of collisions. The line of impact is defined as the line that is parallel to the common normal of the surfaces that are closest or in contact during impact. This is the line along which the collision's internal force acts during impact, and Newton's coefficient of restitution is defined only along this line. Collisions are of three types:
-Perfectly elastic collision
-Inelastic collision
-Perfectly inelastic collision.

In the above example,
Initial momentum
\[1\text{ }=\text{ }mv=2\times 2.5=5\,kgm/s\]
The initial momentum of an object
\[-2\text{ }=\text{ }mx\text{ }\left( -v \right)\]
\[\Rightarrow 2\times (-2.5)\]
\[-5\,kgm/s\]
The momentum of the combination of two after the collision,
\[5+(-5)=0\]
\[\text{velocity of combination} =\dfrac{\text{Momentum of combination}}{\text{Mass of combination}}\]
\[\therefore \text{velocity of combination}=\dfrac{0}{4}=0\]
Thus, the velocity of the combined object after the collision is zero.

Hence, the correct answer is option C.

Note:The following are some examples of colloquial uses of the word collision:
-At least one vehicle is involved in a traffic collision.
-A mid-air collision between two planes occurs.
-A ship collision occurs when at least two moving maritime vessels collide; the related term, allision, describes when a moving ship collides with a stationary object (often, but not always, another ship).