Question

A ball moving with momentum of 5kgmetre second strikes against a wall at an angle of 45 and is reflected at same angle.calculate the change in its momentum

Answer 1

let initial momentum =p1 final momentum =p2
Change in momentum =p2-p1=AB
FROM FIGURE

$ab = \sqrt{ {p1}^{2 } + {p2}^{2} }$
so
$ab = \sqrt{ {5}^{2} + {5}^{2} } = \sqrt{50 } = 7.07 \: kg \: \frac{m}{s}$
hope this helps you