A body of mass 5 kg starts from the origin with an intial with an intial velocity ` vec (u) = 30hat(i) + 40hat(j).` . If the body collides with a wall and after collision its velocity becomes` vec(v) = - 30 hat (i) + 40 hat (j) ,` then what is change in momentum of body ?

Explanation

` vec(P)_(i)= mvec(u) = 5{30 hat(i) + 40 hat (j)}= 150 hat(j) + 200 hat(j) `
` vec (P)_(f) = m vec(u) = 5 { -30 hat(i) + 40 hat(j)} = - 150 hat (i) + 200 hat (j) `
` Delta vec(P) = vec(P)_(f) - vec(P)_(i) = ( - 150 hat(i) + 200 hat (j)) - ( 150 hat(i) + 200 hat(j)) `
` = - 150 hat (i) + 200 hat (j) - 150 hat(i) - 200 hat(j) = -300 hat(i)`