A presentation for classical mechanics where we discuss why air bubble packaging is an example of impulse.

1. Presentation for
CLASSICAL MECHANICS
By: Ayesha Anum (F20BPHY002)
1

2. Air bubble packing for
fragile objects is an
example of impulse.

3. What is Momentum?
3

4. “
“Momentum is the product of the mass
of a particle and its velocity.”
4

5. Represented by:
Symbol “p”
Formula:
p = m v
Unit:
kg • m/s.
Depends on:
◉ How fast object moves
◉ How much object moves
You can also split your content
Examples:
◉ A baseball flying through the air.
◉ A heavy truck moving.
◉ A bullet fired from a gun
Momentum
5

6. ◉ If we consider a car in motion, it
will also have a momentum of:
p= mv
◉ A force must be applied over
some duration of time to bring
the car to rest.
◉ There are two ways to stop the
motion of the car by force.
◉ A small force acting over a long
time will do it if you take the foot
off the gas and let the road’s
friction stop the car.
You can also split your content
◉ A large force acting over a short
time could do it like firmly
applying the brakes to the tires.
This is where concept of impulse
comes in.
Example of a moving car
6

7. What is Impulse?
7

8. “
“Impulse is a term that quantifies the
overall effect of a force acting over
time.”
8

9. Represented by:
Symbol “J”
Formula:
Impulse = Force × (final time – initial
time)
Impulse = Force × Δt
J = F x Δt
Unit:
Newton-seconds
You can also split your content
Impulse
9

10. Relation between impulse and momentum
10

11. “
“The impulse due to all forces acting on
an object is equal to the change in
momentum of the object.”
11

12. Derivation:
Relationship between impulse
and momentum can be shown
by:
J = F x Δt
J = (ma) x Δt
J= m (∆v/ t)t
J = m ∆v
J = ∆p
You can also split your content
Therefore we can conclude:
“Impulse is the amount of
change in an object’s
momentum.”
Relation between Impulse & Momentum
12

13. ◉ If you fall from a roof onto the
ground, you will hurt.
◉ If you fall from a roof onto a
trampoline, it will not hurt as
much.
◉ The change of momentum won’t
happen instantly.
◉ It will be delivered over the
entire duration of your contact
with the trampoline.
◉ Impulse will be higher, impact is
reduced.
You can also split your content
Without and with trampoline:
Same phenomenon applied in air
bubble packaging.
Example of trampoline
13

14. What is air bubble packaging?
14

15. “
“Bubble Wrap is a plastic sheet with air
bubbles that people use to safeguard
things while being moved from one
place to another.”
15

16. ◉ Bubble wrap refers to a
protective plastic sheeting used
to prevent fragile items from
breaking when they are moved
or shipped.
◉ Two sides: 1. One side of the
sheet is flat 2. The other side is
has small, round plastic bubbles
filled with air.
◉ Bubble wrap is usually sold in
long rolls or large, flat sheets.
You can also split your content
Benefits:
1. Used more than once
2. Adaptable and versatile
3. Light in weight
Bubble Wrap
16

17. ◉ It is made with polyethylene resin in
form of beads.
◉ The bubbles in the wrap aren't
completely blown up.
◉ There's extra plastic otherwise it
would pop and lose all its ability to
absorb as much force upon impact
and with the extra space.
◉ This provides cushioning for when
force is applied.
◉ Thus it cushions the impact from
when it hits the floor.
You can also split your content
◉ It absorbs the impact and the force
goes on the bubble wrap and not on
not as much onto the object the
bubble wrap is wrapped around.
Design of bubble wrap
17

18. ◉ Bubble wrap weakens the force or
intensity of the object when it falls, or
hits something.
◉ It acts as a shock absorber.
◉ Helps to absorb the kinetic energy of
the object colliding with its
surroundings.
◉ Bubble wrap provides a force by
time, which is known as impulse.
◉ The more time the force has to act
on the object to slow it down
You can also split your content
◉ Damage caused is lessened to the
object or person that the bubble
wrap is wrapped around.
Why bubble wrap?
18

19. ◉ We wrap a box in bubble wrap and
drop it on the floor.
◉ Bubble wrap is like a crumple zone.
◉ The trapped air in the bubbles
crumples up when the parcel
wrapped is dropped.
◉ The crumpling process takes time
which means that the change in
momentum lasts longer.
◉ So the rate of change of momentum
is less so the force that would break
or scratch the package is reduced.
You can also split your content
◉ It lengthens the impulse which
makes the impact lower.
◉ Thus, damage caused is lessened
to the object or person that the
bubble wrap is wrapped around.
How does bubble wrap work?
19

20. “
We conclude:
“Air bubble packing for fragile objects is
an example of impulse.”
20

21. Thank You
For watching!
21