Question:
A block of mass $2.00 \mathrm{~kg}$ moving at a speed of $10.0 \mathrm{~m} / \mathrm{s}$ accelerates at $3.00 \mathrm{~m} / \mathrm{s}^{2}$ for $5.00 \mathrm{~s}$. Compute its final kinetic energy.
Solution:
Final speed $v=u+$ at
$=10+3 \times 5$
$v=25 \mathrm{~m} / \mathrm{s}$
Now,
$K . E .=\frac{1}{2} m v^{2}$
$=\frac{1}{2} \times 2 \times 25^{2}$
K.E. $=625 \mathrm{~J}$