Question

A child threw a stone straight down off a high bridge. The initial velocity of the stone was 15.0 m/s (include units and proper significant figures). How fast was the stone moving the instant before it hit the river 3.00 sec later?

Answer 1

Answer:

The speed of the stone before it hit the river 3.00 sec later. Let v is the velocity at that instant is 45 m/s.

Explanation:

Given that, a child threw a stone straight down off a high bridge.

Initial velocity of the stone, u = 15 m/s

We need to find the speed of the stone before it hit the river 3.00 sec later. Let v is the velocity at that instant. When it come down, it is moving under the action of gravity. Using equation of motion as :

$v=u+gt\\\\v=15+10\times 3\\\\v=45\ m/s$

So, the speed of the stone before it hit the river 3.00 sec later. Let v is the velocity at that instant is 45 m/s.