Impulsive force (slideshow)

physics chapter 2 slideshow by idrul nafiz

1. WINTER
Template
01
Are you ready to learn?

2. 02
IMPULSE AND
IMPULSIVE
FORCE

3. 03
LEARNING OUTCOMES
•Define impulse and impulsive force
•Explain the effects of increasing or
decreasing time of impact on
impulsive force
•Describe situations where an
impulsive force is beneficial
•Solve problems involving impulsive
force

4. 04

5. 05
DEMONSTRATION

6. WINTER
Template
06
DESIGN AN EXPERIMENT
What can we do to investigate the
impulsive force?
Materials:
Eggs
Newspapers
Sponges

7. 07
Relationship between contact
time and force
•Manipulated variables: ??
•Responding variables: ??
•Controlled variables:??

8. 08RESULT & OBSERVATION
Surface
types
Contact
time
Observation
on egg
Force
Table Longer /
Shorter
Break / Did
not break
Larger /
Smaller
Sponge Longer /
Shorter
Break / Did
not break
Larger /
Smaller
t
F
1
µ

9. 09
Relationship between force and
change in momentum
Before
After
Is the egg experience any
changes in momentum?
mup
initial=
mvp
final
=

10. 10
•So, the change in momentum is:
•What happens to the force when
the change of momentum is
higher?
initialfinal
ppp -=D
mumvp -=D
pFDµ

11. WINTER
Template
11
CONCLUSION
-The contact time on impact is affected
by the hardness of surface. The harder
the surface, the shorter the contact time
on impact
-When contact time is shortest, the force
of impact will be larger
-The force is directly proportional to the
change in momentum

12. 12
•Relationship with impulsive force
•Impulsive force:
•So, the impulsive force is the rate of
change of momentum
pFDµ
t
F
1
µ
t
mumv
F
-
= NkgmsF /
2-
=

13. Example:
A bullet of mass 50 g is shot and it
travels at a velocity of 100 m/s towards
a target and takes 0.01 seconds to
come to a stop. What is the impulsive
force hitting the target?

14. •HOW ABOUT IMPULSE?
•Impulse is defined as the changes of
momentum
mumvFt -=
Nskgms/
1-
=

15. Example:
•Figure shows a ball of mass 20 g travelling
at 15m/s. It hits a wall and bounces back
in opposite direction with a velocity of
12m/s. What is the impulse of the ball?

16. 13
APPLICATION OF IMPULSIVE
FORCE
Both cars travel at a velocity of 120 m/s
and hits a wall. Why does the impact on
car A is smaller compared to car B?
A B

17. •Diagram 2 shows a baseball player
wearing a soft thick glove to catch a ball
during a baseball match. Compare the
impulsive force if the baseball player
wears a hard glove to catch the ball.

18. 14
•Why a karate expert can break a pile of
plank easily using his bare hand?

19. •Why does food stuff such as garlic can
be pounded using mortar and pestle?

20. 15
What are other applications of
impulsive force in our daily lives?
Can you explain??

21. WINTER
Template
16
Do you want to play some
games?
INSTRUCTIONS:
-You are allowed to discuss during the game
-The task for each player is to calculate the
questions given
-Given that initial velocity of the ball is 0 ms
-1
and
mass of the ball is 2 kg. The result of the
calculation will determine whether it’s a goal or a
miss

22. 17
Kick no.Final
velocity
(v)
Time of
impact (t/
s)
Impulsive
force
(F/N)
Result of
the kick
1 45 0.3 300 GOAL /
MISSED
2 25 0.2 250 GOAL /
MISSED
3 30 0.6 100 GOAL /
MISSED
4 30 0.2 300 GOAL /
MISSED
5 30 0.6 100 GOAL /
MISSED
6 10 0.8 25 GOAL /
MISSED
Initial velocity (u) = 0
m/s
Mass of ball (m) = 2kg

23. 18
What have you learn today?
•Impulse as rate of change of momentum
•Impulsive force as the rate of change of
momentum in a collision between 2 objects
•Explain the effect of increasing & decreasing
time of impact on the magnitude of the impulsive
force
•Describe situations and solve problems involving
impulsive force
mumvFt -=
t
mumv
F
-
=