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a woman drops a rock from a bridge to the water 17.5 m below. with what speed does the rock strike the water?

a. 0 m/s
b. 18.5 m/s
c. 171m/s
d. 9.8 m/s
e. 17.5 m/s

Respuesta :

Given :

Height from which rock is dropped, h = 17.5 m.

Initial velocity, u = 0 m/s.

To Find :

Speed does the rock strike the water.

Solution :

We know, by equation of motion :

[tex]v^2-u^2=2as[/tex]      ......( 1 )

Here , a = g = 9.8 m/s² ( Acceleration due to gravity )

Putting all given values in 1 , we get :

[tex]v^2-u^2=2as\\\\v=\sqrt{2gh}\\\\v=\sqrt{2\times 9.8\times 17.5}\ m/s\\\\v=18.5\ m/s[/tex]

Therefore, speed with rock strike the water is 18.5 m/s.

Hence, this is the required solution.