MCQ
A ball moving with a momentum of $5\ \ce{kgm/ s}$ strikes against a wall at an angle of $45^\circ$ and is reflected at the same angle. The change in momentum will be $\ce{(kg-m/ s):}$
- ✓$7.07$
- B$14.14$
- C$8.00$
- D$7.5$
✓
Answer
Correct option: A.
$7.07$
$\triangle\text{p}=2\text{mv}\cos\theta$
$=2\text{p}\cos\theta$
$=2\times5\times\frac{1}{\sqrt{2}}$
$=7.07$
$=2\text{p}\cos\theta$
$=2\times5\times\frac{1}{\sqrt{2}}$
$=7.07$
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