applications of the concept of impulse
Answers
Welcome to the concept of Impulse
Grade :- 11th Standard
1. A cricket player lowers his hands while catching a cricket ball : As you have noticed many times, the player draws in his hands backward in the act of catching the ball. Thus he allows a longer time for his hands to stops the ball.
As Impulse = force × time = change in linear momentum
or force = change in momentum/time.
Therefore, by increasing the time of a catch, the player has to apply a smaller force against the ball in order to stop it. The ball in turn. exerts a smaller force on his hands and his hands are not injured.
It should be clearly understood that force depends not only on the change in momentum, but also on how fast the change is brought about. The same change in momentum brought about in a shorter time needs a greater force and vice-versa.
2. When a person falls from a certain height on a cemented floor:- The floor does not yield. The total change in linear momentum is produced in a smaller interval of time. Therefore, as explained above, the floor exerts as much larger force. Due to it, a person receives more injury.
On the other hand, when a person falls on a heap of sand, the sand yields. The same change in linear momentum is produced in much longer time. The average force exerted on the person by the heap of sand is therefore, much smaller and hence the person is not hurt.
3. China wares and glasswares are wrapped in paper or straw pieces:- Before packing, in the event of fall, impact will take a longer time to reach the glass/chinawares through paper/straw. As a result, the average force exerted on the china or glasswares is small and chances of their breaking is reduced.
4. The vehicles like scooter, car, bus, truck etc are provided with shock absorbers. When they move over an uneven road, impulsive force are exerted by the road. The function of shock absorbers is to increase the time of impulse. This would reduce the force experienced by the rider of the vehicle.
5. It is difficult to catch a cricket ball than to catch a tennis ball. The cricket ball being heavier has much larger momentum and therefore, exerts a much larger force on the hands during catch, in comparison to the force exerted by the tennis ball.