Question

A ball strikes a horizontal floor at ${45}^{\circ }.25$ of its kinetic energy is lost collision. Find the coefficient of restitution

• A. $1$
• B. $\frac{1}{\sqrt{2}}$
• C. $\frac{1}{\sqrt{4}}$
• D. $\frac{1}{4}$

Answer 1

The correct option is A $1$

Fraction of $kE$ cost

$=$final $kE$/ initial $kE$

Final velocity $=v=\sqrt{{\left(\frac{u}{\sqrt{2}}\right)}^2+{\left(\frac{eu}{\sqrt{2}}\right)}^2}$

Fraction of $kE$ cost$=\frac{\frac{1}{2}m{v}^2}{\frac{1}{2}m{u}^2}$