# A projectile is shot from the ground at a velocity of 86 m/s and at an angle of (2pi)/3. How long will it take for the projectile to land?

May 19, 2017

$15.2 S e c$

#### Explanation:

We know for non inertial frame of reference we have Newtons Laws of motion Valid We can Use the same here

On the Object we have $g$ acting downwards and U (velocity) has components which we have shown .

From Newtons laws of motion we get
$V = U + a t$

if we apply the same here we get
$- U \sin \theta = U \sin \theta - g \text{t}$

similarly we substitute the values to get

$t = \frac{2 \cdot U \sin \theta}{g}$
$t = \frac{2 \cdot 86 \sin \left(\frac{2 \pi}{3}\right)}{9.8} = 15.2 S e c$