Question

11. A ball is thrown in horizontal direction from a height of 10 m with
20m/s. (a) How far will it hit the ground from its initial position and​

Answer 1

Answer:

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Answer 2

Answer:

Given that,

Initial speed = u

Height = 20 m

This speed will remain constant throughout the journey.

Horizontal component of velocity when it hits the ground is

v

x

=u

if v

y

be the vertical component of velocity when it hits the ground then,

v

y

2

=2gh

v

y

2

=2×9.8×20

v

y

2

=392m

2

/s

2

Now, final speed of object

=

v

x

2

+v

y

2

=

u+392

Now, according to question

u+392

=3u

9u

2

=u

2

+392

8u

2

=392

u

2

=49

u=7m/s

Hence, the final velocity is 7 m/s