The product of the mass of the particle times the speed of that same particle is called the linear momentum of that particle. When the entire net external force working on a system of bodies is always zero, the system’s momentum stays constant because of the law of conservation of linear momentum. If two distinct bodies clash and no external force works on them, the initial and final momentum will remain the same after the crash. If the total amount of momentum never varies, then it is a property of conservation of momentum.
We can represent this as,
Initial momentum = Final momentum
Pi = Pf
If P is the linear momentum, v is the linear velocity and m is the mass of the body then the linear momentum can be expressed as,
P = mv
If the total net external force acting on any object/body is zero, then the rate of momentum change is zero. From this, we can conclude that there is no change in momentum.
Read More – Law of Conservation of Linear Momentum
Important Questions with Answers
1. What are the applications of the law of conservation of linear momentum?
Rocket launches are examples of conservation of momentum. The rocket fuel burns, pushing the exhaust gases downwards and the projectile upwards. One more example is the motorboat. Motorboats operate on the same principle, pushing the water backwards and forward in response to conserve momentum.
2. What is Newton’s second law of motion?
Newton’s second law states that an object’s acceleration is determined by the object’s mass and the total net force acting on the object. The acceleration of any object is inversely proportional to its mass, and it is proportional to the net force acting on it. The acceleration of an item increases as the force pressing on it increases. Similarly, as an object’s mass increases, the object’s acceleration decreases.
3. What is the formula for the law of conservation of linear momentum?
Linear momentum is the product of an object’s mass (m) and velocity (v). When an object has more momentum, it is more difficult to stop.
The linear momentum formula is,
p = mv.
The total amount of momentum never varies, and this phenomenon is known as momentum conservation.
4. Define the law of conservation of linear momentum.
If the total net external force acting on a system of bodies is zero, the system’s momentum remains constant, according to the law of conservation of linear momentum.
5. Give an example of the law of conservation of linear momentum.
Let us consider objects of two masses: M and m. These two objects travel in opposite directions at speeds v. If they clash and then move together, we must calculate the system’s velocity.
Momentum will be conserved because no external force is exerted on the system of the two bodies.
Initial momentum = Final momentum
( Mv – mv ) = ( M + m ) VFinal
By using this equation, the system’s final velocity can be easily calculated.
6. Give the applications of Newton’s second law.
Newton’s second law of motion can be used to find the amount of force required to move or stop an item.
A few examples of Newton’s Second Law are,
- Pushing a cart
Pushing a cart in which one is empty is more effortless than pushing a cart in which one is loaded in a supermarket because more mass needs more acceleration.
- Two people are walking.
If one of the two people walking is fatter, the fatter person will walk slower since the acceleration of the lighter person is more excellent.
7. How much net horizontal force is required to accelerate a 500 kg car at 3 m/s2?
Newton’s 2nd law is related to an object’s mass, the net force applied to it, and its acceleration, from this, we can find the force as,
Fnet = ma
Here, we have the value of mass and acceleration. Let’s substitute the values in the above equation. We get,
500 kg × 3 m/s2 = 1500 N
The horizontal net force, which is 1500 N, is needed to accelerate a 500 kg car at 3 m/s-2 .
8. What if momentum is not conserved?
If gravity, friction, or net force is present, momentum is not preserved; here, the net force means the total amount of force. It shows that its momentum will vary if these quantities act on any object. This should be noticeable because you are changing the velocity and momentum of the object.
9. Linear momentum is a _____.
- Dimensionless quantity
- Scalar quantity
- Vector quantity
- None of the above
Answer: b. Vector quantity
Explanation: Linear momentum is a vector quantity.
10. Write the equation of the law of conservation of linear momentum
Newton’s second law of motion can describe the law of conservation of linear momentum. According to Newton’s second law of motion, the rate of change of an object’s linear momentum is equivalent to the total net external force applied to the object.
It is mathematically stated as:
If an object’s total net external force is zero, the rate of momentum change is again zero, signifying that there is no difference in momentum.
Practice Questions
- What is an example of the law of conservation of momentum from everyday life?
- What happens to the linear momentum when the force is absent?
- How is impulse related to linear momentum?
- Why can momentum be conserved when energy is not?
- Is momentum conserved during the collision?
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