projectile motion problem with no initial velocity given

AI Thread Summary
To solve the projectile motion problem where a tennis ball is thrown from a height of 2m at a 40Ā° angle and travels 250m before hitting the ground, start by applying the relevant kinematic equations for both horizontal and vertical motion. The initial velocity is unknown, so work symbolically to express the initial velocity in terms of the given quantities. It is suggested to simplify the problem by ignoring the initial height and considering the range as 250m to find the initial speed. The discussion emphasizes the importance of showing effort in problem-solving, as required by homework guidelines. Understanding the relationships between the variables will lead to the solution for the initial velocity.
jrm1508
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New user has been reminded to always show their work on schoolwork problems.
Homework Statement
A tennis ball is thrown from an elevation of 2m, at an angle of 40Ā°. If the ball travels 250m
before it hits the ground, what velocity was it thrown at?
Relevant Equations
Kinematic equations.
I don't know how to solve projectile motion problems when there was no initial velocity given, also no final velocity, or time. Please helpšŸ˜­
 
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jrm1508 said:
Homework Statement: A tennis ball is thrown from an elevation of 2m, at an angle of 40Ā°. If the ball travels 250m
before it hits the ground, what velocity was it thrown at?
Relevant Equations: Kinematic equations.

I don't know how to solve projectile motion problems when there was no initial velocity given, also no final velocity, or time. Please helpšŸ˜­
Start by writing down the equations for x and y. See where that takes you.
 
The homework rules of PF requires you to show at least some effort to find the solution yourself.

The problem is literally to find the initial velocity. I suggest you work symbolically to find expressions involving the quantities given in the problem and the initial velocity. Preferably starting from the relevant equations that you did not write. (Please write out the equations you think are relevant).
 
jrm1508 said:
Homework Statement: A tennis ball is thrown from an elevation of 2m, at an angle of 40Ā°. If the ball travels 250m
before it hits the ground, what velocity was it thrown at?
Relevant Equations: Kinematic equations.

I don't know how to solve projectile motion problems when there was no initial velocity given, also no final velocity, or time. Please helpšŸ˜­
The initial speed is ##u## and the time of flight is ##\Delta t##.

PS if you are really stuck with this, forget about the initial height above the ground and take the range to be ##250m##. Can you find ##u## in that case?
 
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