Why do we feel heavier or lighter at differenthis parts of the lift?

[animerawkz]

Hi, i am currently doing a project on these questions.


1)why do we feel heavier when the lift startes to move up?

2) why do we feel normal in the middle?

3) why do we feel lighter when the lifts comes to a stop?


although i know that the three laws of Newton is somehow related to it, i still can't find the connection between them.

all types of help and explanation is greatly appreaciated..

thanks

 

[daniel_i_l]

The weight that you feel is equal to the Normal force that the floor pushes you with. When you're in an elevator for example, when it first starts moving up it accelerates and you feel that acceleration as weight. The acceleration up makes the Normal force get bigger (f=ma). In the middle of the ride you're in constant motion so you don't feel anything unusual, constant speed does't have any effect on the Normal force. When you come to a stop you deaccelerate, this causes a force in the oppisite direction of the normal force (which is in the direction of the movement) and so you feel lighter.