Question

. A body of mass 2 kg is projected with speed
The 1200 m/s at angle of 45° with the horizontal.The change in momentum of body after time t = 2 s is (g = 10 m s-2)
(1) 20 Ns
(2) 10 Ns
(3) 40 Ns
(4) 30 NS

pls answer step wise
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Answer 1

Answer:answer is 40ns

Explanation:

We all know that if external force is not applied the momentum of the system is conserved. Here change in momentum is mu=mv

V in x direction remains same I.e.

1200.cos45=600√2i

V in y direction changes as follows

V(y)=u(y)+a(y)t

V(y)=(1200.sin45)j -10(2)j

=(600√2 -20)j

We know that change in momentum is

Mv-mu=2×{(600√2)i+(600√2-20)j}-2{(600√2)I+(600√2)j}=-40n

I hope this solution is clear. If you have any query just tell me