The document discusses momentum and Newton's second law of motion. It defines linear momentum as the product of an object's mass and velocity. Newton's second law is stated as the net external force equals the change in momentum divided by the change in time. The law of conservation of momentum states that the total momentum of an isolated system before and after an interaction, such as a collision, remains the same.
2. INDEX
Linear momentum
Examples of momentum
Momentum and Newton’s seconds law
Mathematical analysis of momentum
and newton’s second law.
Law of conservation of momentum
Examples
Quiz
3. LINEAR MOMENTUM
Momentum is directly proportional to the
object’s mass and also its velocity. Thus the
greater an object’s mass or the greater its
velocity, the greater its momentum. Momentum
P is a vector having the same direction as the
velocity v.
The SI unit for momentum is kg·m/s and can
also be expressed as Ns
Linear Momentum: Linear momentum is
defined as the product of a system’s mass
multiplied by its velocity. In symbols, linear
4. Examples of Momentum:
1.A semi-truck full of logs has a large mass and must
slow down long before a stop light because even with
a small velocity, it has a large momentum and is
difficult to stop.
2.A four-wheeler moving at a relatively fast velocity has
a smaller momentum than the semi-truck because of its
small mass and will stop much faster.
3.A bullet, although small in mass, has a large
momentum because of an extremely large velocity.
5.
6. Momentum and Newton’s
Second Law
Momentum was deemed so important that it was
called the “quantity of motion.” Newton actually
stated his second law of motion in terms of
momentum: The net external force equals the
change in momentum of a system divided by the
time over which it changes. Using symbols, this law
is
Fnet=Δp/Δt
,where Fnet is the net external force, Δp is the
change in momentum, and Δt is the change in time.
(when a net force acts on a body, it produces acceleration in
7. Newton’s second law and linear
momentum (mathematical analysis)
According to the Newton’s second law of motion,
F=ma (1)
Since acceleration a is defined as the rate of change of
velocity,
a=∆v/ ∆t (2)
Put equation (2) in equation (1)
F=m ∆v/ ∆t
By rearranging the above equation we get,
F= ∆(mv)/ ∆t (3)
Now, as we know that,
P=mv (4)
We put equation (1) in equation (3)
F= ∆p/ ∆t
Or F= P2-P1/t2-t1
8.
9. Law of conservation of
momentum
The law of conservation of momentum states that for two
objects colliding in an isolated system, the total momentum
before and after the collision is equal (remains constant).
This is because the momentum lost by one object is equal to
the momentum gained by the other .Conservation of
momentum is derived from Newton's laws of motion.
Newton's third law states that every action has an equal but
opposite reaction; the force that one object A exerts on
object B is equal but opposite to the force that object B
exerts on object A. By Newton's second law, this force is
equal to the product of the mass and the acceleration of the
objects, so the product of the mass and acceleration of
10.
11. True or False
1. Momentum is inversely proportional to the object’s mass and
velocity
TRUE FALSE
2. Momentum is a vector quantity
TRUE FALSE
3. Momentum can be represented by the symbol ‘m’
TRUE FALSE
4. Einstein stated the second law in terms of momentum
TRUE FALSE
5. Net force is the total external force applied on a body
TRUE FALSE
6. The momentum lost by one object is equal to the momentum
gained by the other
TRUE FALSE
7. To every action there is an equal but reverse reaction
TRUE FALSE
12. MCQs
1. The units for momentum are
a. kg
b. m/s
c. kg-m/s
d. kg/m/s
2. The formula for momentum is
a. mass divided by velocity
b. mass multiplied by velocity
c. velocity divided by mass
d. Force times acceleration
3. The law of conservation of momentum states that,
a. p before is less than p after
b. p before is the same as p after
c. p before is more than p after
13. 4. The difference between a car hitting a wall vs. a car
hitting a hay stack is
a. the Impulse on the car hitting the wall is greater
b. the change in momentum of the car hitting the wall is
greater
c. the force on the car hitting the hay stack is greater
d. the collision time of the car hitting the hay stack is
greater
5. A 0.250 kg cart moving at 0.400 m/s has how much
momentum?
a. 0.1 kg-m/s
b. 1 kg-m/s
c. 10 kg-m/s
d.100 kg-m/s
14. Answer the following Questions
What is meant by linear momentum?
Ans: Linear momentum is defined as the product of a
system’s mass multiplied by its velocity.
Give an example of law of conservation of
momentum?
Ans: A system of gun and a bullet .Before firing the
gun, both the gun and the bullet are at rest ,so the
total momentum of the system is Zero .As the gun is
fired, bullet shoots out of the gun and acquires
momentum .To conserve momentum of the system
,the gun recoils .According to the law of conservation
of momentum ,the total momentum of the gun and the
bullet will be zero after the gun is fired.
15. What is the Newton's second law of motion?
Ans: when a net force acts on a body, it produces
acceleration in the direction of the net force. The
magnitude of this acceleration is directly
propotional to the net force acting on the body
and inversely propotional to its mass
mathematically: F=ma
What is the SI unit of momentum?
Ans: The SI unit for momentum is kg · m/s and
can also be expressed as Ns