Question

A stone is projected up with a velocity of 14.7 ms-1 from the top of a tower and it reaches the ground after 5 seconds. Then height of that tower is (a) 9.8 m (b) 19.6 m (c) 49 m (d) 98 m​

Answer 1

Answer:

9.8m

Explanation:

Initial velocity of the stone u=−4.9m/s  (upwards)

Acceleration of the stone  g=9.8m/s  

2

  (downwards)

Time taken by the stone to fall down in water  t=2 s

Height of the bridge  H=ut+  

2

1

​

gt  

2

   (Taking downward direction to be positive)

∴  H=(−4.9)(2)+  

2

1

​

(9.8)(2)  

2

=9.8 m

Answer 2

The height of the tower of 9.8m

GIVEN: A stone is projected up with a velocity of 14.7 ms-1 from the top of a tower and it reaches the ground after 5 seconds.
TO FIND: Height of that tower
SOLUTION:

As we are given in the question,

The initial velocity of the stone u=−4.9m/s  (upwards)

Acceleration of the stone  g=9.8m/s  (downwards)

Time is taken by the stone to fall in water t = 2 s

Height of the bridge  H=ut

(Taking a downward direction to be positive)

H=(−4.9)(2)

H=9.8 m

Therefore,

The height of the tower of 9.8m

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