Question

Antonina throws a coin straight up from a height of 1.2m above the water surface in a fountain. The coin strikes the water 1.3s later. We want to know the vertical velocity of the coin at the moment it strikes the water. We can ignore air resistance.

Which kinematic formula would be most useful to solve for the target unknown?

Answer 1

Answer: v=1,56(m/s)

Explanation: Called: g(Gravity acceleration) =10
`m/s^(2) \\`(or 9,8
`m/s^(2)`)

h=1,2m ; t=1,3s

Because the coin fell freely, the velocity is calculated by the formula:

v=
`√(2gh)` (1)

besides, you have time to touch the bottom of the water is 1,3s:

t=
`\sqrt(2g)/(h) }` (2)

(1) and (2) => v=1,56 (m/s)