Calculating Velocity of Ball at Impact with Ground

[Trandall]

Homework Statement

A ball is thrown at a velocity of 10 m/s, at an angle of 30° from horizontal and released 2 m
above the ground. What will the magnitude of ball’s resultant velocity be at the moment of
impact with the ground?

Homework Equations

Vf2 = vi2 + 2as

The Attempt at a Solution

Vf2 = 5(2) + 2 x -9.8 x -2
Vf2 = 25 + 39.2
Then find the square root

The answer is 11.8 m/s
What am I doing wrong, please help

Thanks

 

[rock.freak667]

The Attempt at a Solution

Vf2 = 5(2) + 2 x -9.8 x -2
Vf2 = 25 + 39.2
Then find the square root

The answer is 11.8 m/s
What am I doing wrong, please help

Thanks

Split the velocity into components.

Use v²=u²-2g(s-s₀) to find the vertical component of velocity when it hits the ground.

 

[Trandall]

Im sorry, I am still stuck, could you write it out in the formulae, I am clueless when it comes to physics.

 

[rock.freak667]

Im sorry, I am still stuck, could you write it out in the formulae, I am clueless when it comes to physics.

v²=u²-2g(s-s₀)

v= final velocity
u= initial velocity
g= acceleration due to gravity
s= displacement
s₀=initial displacement

 

[graphene]

you'll have to analyze motions in the x & y direction separately as acceleration is along the y direction only.

X
{v}_{x0} = 10 \cos 30
{a}_{x} = 0
{v}_{x} = {v}_{x0}

Y
{v}_{y0} = 10 \sin 30
{a}_{y} = -g
{s}_{y} = -2

{s}_{y} = {v}_{y0}t + \frac{1}{2}{a}_{y}{t}^{2}
solve for t & then use -
<br /> {v}_{y} = {v}_{y0} + {a}_{y}t

 

[Trandall]

Thanks heaps for your help =)