Your friend drops your house keys down to you from their second floor window. If you catch them 2.4 m from where your friend dropped them, what is the velocity of the keys when you catch them? a.

-6.9 m/s

c.

-7.2 m/s

b.

-6.5 m/s

d.

-7.4 m/s

The word drop means that the initial velocity of the house keys is 0 m/s. The relationship between the distance and the velocity is given by the equation,

2gd = (Vi) ² - (Vf) ²

where g is the acceleration due to gravity equal to - 9.8 m/s². Subsituting the given,

2 (-9.8 m/s²) (2.4 m) = 0 - (Vf) ²

The value of Vf is - 6.86 m/s. Thus, the answer is letter A.