Impulsive Force
- Impulsive force is defined as the rate of change of momentum in a reaction. Mathematically, we write
- It is a force which acts on an object for a very short interval during a collision or explosion.
Example:
A car of mass 1000kg is traveling with a velocity of 25 m/s. The car hits a street lamp and is stopped in0.05 seconds. What is the impulsive force acting on the car during the crash?
Answer:
m = 1000kg
u = 24 m/s
v = 0
t = 0.05s
A car of mass 1000kg is traveling with a velocity of 25 m/s. The car hits a street lamp and is stopped in0.05 seconds. What is the impulsive force acting on the car during the crash?
Answer:
m = 1000kg
u = 24 m/s
v = 0
t = 0.05s
Effects of impulse vs Force
- A force determines the acceleration (rate of velocity change) of an object. A greater force produces a higher acceleration.
- An impulse determines the velocity change of an object. A greater impulse yield a higher velocity change.
- Playing football
- Playing badminton
- Playing tennis
- Playing golf
- Playing baseball
Long Jump
![](http://www.one-school.net/Malaysia/UniversityandCollege/SPM/revisioncard/physics/forceandmotion/images/longjump.jpg)
- The long jump pit is filled with sand to increase the reaction time when atlete land on it.
- This is to reduce the impulsive force acts on the leg of the atlete because impulsive force is inversely proportional to the reaction time.
High Jump
![](http://www.one-school.net/Malaysia/UniversityandCollege/SPM/revisioncard/physics/forceandmotion/images/highjump.jpg)
(This image is licenced under the GNU Free Document Licence. The original file is from the Wikipedia.org.)
- During a high jump, a high jumper will land on a thick, soft mattress after the jump.
- This is to increase the reaction time and hence reduces the impulsive force acting on the high jumper.