Question

A particle of mass $10\text{kg}$ is thrown at an angle of ${37}^{\circ }$ with horizontal with an initial velocity of $5\text{m/s}$. The kinetic energy of the projectile when it just reaches the ground will be

• A. $250\text{J}$
• B. $125\text{J}$
• C. $100\text{J}$
• D. $80\text{J}$

Answer 1

The correct option is B $125\text{J}$

Using law of conservation of energy,
$K_i+U_i=K_f+U_f$
Since, ($U_i=U_f$; as initial and final height of the particle is same )
$\therefore K_i=K_f\Rightarrow K_f=\frac{1}{2}m(u{)}^2=\frac{1}{2}\times 10\times 5^2=125\text{J}$