Question

A projectile is thrown in the upward direction making an angle of $60$ with the horizontal direction with a velocity of $47$ Then the time after which its inclination with the horizontal is $45$

Answer 1

$\theta ={60}^o$

$u=147m/s$

$U_x=147cos60$

$U_y=147sin60$

$X=V_x$

$Y=V_y$

$\frac{V_x}{V_y}=tan45$

$V_x=V_y$

$V_x=U_x=147cos60$

$V_y=U_y-gt$

$147cos60=147sin60-10t$

$73.5=73.5\sqrt{3}-10t$

$10t=73.5(\sqrt{3}-1)$

$t=\frac{73.5(\sqrt{3}-1)}{10}=5.38s$