Given angle and distance traveled find initial velocity

[shaunk]

A ball is pictched at a batter, the batter hits the ball at a 45 degree angle It just clears the outfield fence 98m away Find velocity of the ball when it left the bat. Assume fence is the same height as the pitch. Disreguarding air friction I can't figure out how to find initial velocity.

 

[learningphysics]

How did you approach the problem?

 

[shaunk]

I attempted to break the problem down to its components using Vx= Vcos45 and vy=Vsin45 then used the formula Vx=x/t then 0=Vyit = 1/2gt^2

 

[learningphysics]

I attempted to break the problem down to its components using Vx= Vcos45 and vy=Vsin45 then used the formula Vx=x/t then 0=Vyit = 1/2gt^2

Looks good to me.

so

Vx*t = 90

Vcos45*t = 90
Vsin45*t - (1/2)gt^2 = 0

you've got 2 equations with 2 unknowns... you can simplify the second equation by dividing by t (since the answer we need is not t = 0)...

Vsin45 - (1/2)gt = 0

so solve:

Vcos45*t = 90
Vsin45 - (1/2)gt = 0