Find the height from which the ball was thrown

[xjasonx1]

Homework Statement

A ball is tossed from an upper-story window of a building. The ball is given an initial velocity of 9.00 m/s at an angle of 16.0° below the horizontal. It strikes the ground 5.00 s later. (Ignore air resistance.)
(b) Find the height from which the ball was thrown.

Homework Equations

Y-Yo= Vyot -1/2gt^2

The Attempt at a Solution

Yo= -Vyot +1/2gt^2

Yo= -(9sin16)(5) + 1/2(9.8)(25) = 110m
but the answer is wrong.

 

[ehild]

Consider the sign of vyo.

ehild

 

[Mark44]

Homework Statement

A ball is tossed from an upper-story window of a building. The ball is given an initial velocity of 9.00 m/s at an angle of 16.0° below the horizontal. It strikes the ground 5.00 s later. (Ignore air resistance.)
(b) Find the height from which the ball was thrown.

Homework Equations

Y-Yo= Vyot -1/2gt^2

The Attempt at a Solution

Yo= -Vyot +1/2gt^2

Yo= -(9sin16)(5) + 1/2(9.8)(25) = 110m

Your formula above is incorrect. The ball is tossed out of the window at a downward angle. This means that the vertical component of the velocity is in the same direction as gravity is acting. In your formula, V_y0 is negative, but the gravitational force is positive. You can define which sign corresponds to up or down, but you have to be consistent.

but the answer is wrong.

 

[xjasonx1]

Thank you!