Question

The position co-ordinate of a projectile projected from ground on a certain planet(with no atmosphere) are given by y=(4t-2t2)m & x=(3t) m,,,where t is in second and point of projection is taken as origin.The angle of projection of projectile with vertical is what?????

Answer 1

horizontal and vertical positions of an object at give time t can be marked as
Horizontal position : x = vxt = 3t
Vertical : h = vyt 1/2 at ^2 = 4t - 2t ^2
initial velocity = vy = v cos Ф
Initial horizontal velocity is given as = vx = v sin Ф
Since the given angle are with respect to vertical so 
vertical velocity = vy = 4 m / s 
Horizontal velocity = vx = 3 m / s 
or 
V cos Ф = 4 
v sin Ф = 3
Divide these two equation we get 
tan Ф = 3/ 4 
Ф = tan ^-1 ( 3 / 4 ) 
= 37 degree

Answer 2

Answer:

37°

Explanation:

Velocity can be found by differentiating these terms.

Vy=4-4t

Vx=3

Now, for initial velocity, t=0. So velocity in y would be 4.

We know that Vy/Vx=tan theta.

So, angle=tan-14/3

so the answer is 37°

hope it's useful.