Question

An object is thrown horizontally with speed of 9.8m/s. Find it's displacement in horizontal and vertical direction when horizontal velocity becomes equal to vertical velocity

Answer 1

Answer:

R=u^2*sin2(45)/2*10

=9.8*9.8/20

=4.802m

Answer 2

Bravo! It's an IIT Question!

Correct Question: Object is projected in horizontal with velocity 9.8 m/s. Then find its speed when horizontal & vertical displacement is same.

Answer:

Speed = 22 m/s ( approx )

Explanation:

We know that,

             V = uî + gt j

Now, on carefully observing the question, we find a condition mentioned as  x = y. Now, from this condition, we can write;

        ut = 1/2 gt²  ( equating displacements )

          t = 2u/g_______ (1)

Now,

         V = uî + gt j

         V = uî + g(2u/5) j     [From (1)]

         V = uî + 2u j

        |V| = √u² + 4u²

        |V| = √5u²

        |V| = √5 u

        |V| = √5 × 9.8   [since, given, u= 9.8 m/s]

        |V| = 21.97 m/s

        |V| = 22 m/s (approx )

Therefore, speed of object when horizontal & vertical displacement is same is 22 m/s ( approx ).