A ball of mass 'm' is projected from the ground with aspeed 'u' at an

1.	A ball of mass 'm' is projected from the ground with aspeed 'u' at an angle 'a' with the horizontal. Themagnitude of the change in momentum of the ballover a time interval from begining till it strikes theground again is
Answer» As we know that a projectile motion is a combination to horizontal and verticle motion.The vetical component of intial velocity ‘u’ always remains constant ,i.e. in this case ,ux=ucoso,throughout the motion.So change in momentum in horizonal direction is 0(zero). Now analysing the vertical direction motion we know intial velocity in vertical direction uy=usino. After time t,vy=usino-gt,(using eq. of motion ,v=u+at) Thus, Change in momentum in vertical direction =m.vy-m.uy =m.(usino-gt)-(m.usino) =-mgt

A ball of mass 'm' is projected from the ground with aspeed 'u' at an angle 'a' with the horizontal. Themagnitude of the change in momentum of the ballover a time interval from begining till it strikes theground again is

Answer»

As we know that a projectile motion is a combination to horizontal and verticle motion.The vetical component of intial velocity ‘u’ always remains constant ,i.e. in this case ,ux=ucoso,throughout the motion.So change in momentum in horizonal direction is 0(zero).

Now analysing the vertical direction motion we know intial velocity in vertical direction uy=usino.

After time t,vy=usino-gt,(using eq. of motion ,v=u+at)

Thus, Change in momentum in vertical direction =m.vy-m.uy

=m.(usino-gt)-(m.usino)

=-mgt

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