MCQ
A $1.0\, kg$ ball drops vertically into a floor from a height of $25\, cm$. If rebounds to a height of $4\ cm$. The coefficient of restitution for the collision is
- A$0.16$
- B$0.32$
- ✓$0.40$
- D$0.56$
✓
Answer
Correct option: C.
$0.40$
c
Velocity just before collision $=\mathrm{u}=\sqrt{2 \mathrm{gh}}=\sqrt{5} \mathrm{m} / \mathrm{s}$
Velocity just before collision $=\mathrm{u}=\sqrt{2 \mathrm{gh}}=\sqrt{5} \mathrm{m} / \mathrm{s}$
velocity just after collision $=\mathrm{v}=\sqrt{2 \mathrm{gh}^{\prime}}=\sqrt{0.8} \mathrm{m} / \mathrm{s}$
$\mathrm{e}=\frac{\mathrm{v}}{\mathrm{u}}=0.4$
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