Projectile motion ball throw problem

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SUMMARY

The discussion focuses on solving a projectile motion problem involving a ball thrown from a 25m high building with an initial velocity of 20 m/s at a 30-degree angle. Key equations include the total time of flight, T total = (2Vi sin(theta))/(2(9.81)), and the range equation, R = (Vi)^2 sin(2theta)/(9.81), though the latter is only applicable for ground-level launches. Participants highlight the need to adjust these equations for the initial height and emphasize the importance of considering both initial and final velocities in calculations. The discussion concludes with a recommendation to explore projectile motion equations to determine the time until the ball strikes the ground.

PREREQUISITES
  • Understanding of projectile motion principles
  • Familiarity with trigonometric functions (sine and cosine)
  • Knowledge of kinematic equations for vertical motion
  • Basic algebra for solving equations
NEXT STEPS
  • Review the complete set of projectile motion equations in your textbook
  • Learn how to derive time of flight for projectiles launched from an elevated position
  • Investigate the effects of initial height on projectile range and impact velocity
  • Practice solving similar problems involving different angles and initial velocities
USEFUL FOR

Students studying physics, particularly those focusing on mechanics and projectile motion, as well as educators seeking to enhance their teaching of these concepts.

herbgriffin
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Homework Statement


A ball is thrown upwards from the top of a building with an initial velocity of 20 m/s and at an angle of 30 (degrees) with the horizontal. The height of the building from the ground level is 25m. Determine (i) where and when it will strike the ground (ii) velocity with which it strikes the ground (iii)maximum height reached by the ball above the ground level.

Homework Equations


T total = (2Vi sin(theta))/2(9.81)
Range, R= (Vi)^2 sin2(theta)/ (9.81)


The Attempt at a Solution


i have solve for Vx= 20cos30 = 17.32 m/s
Vy=20sin30= 10 m/s
 
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herbgriffin said:

Homework Statement


A ball is thrown upwards from the top of a building with an initial velocity of 20 m/s and at an angle of 30 (degrees) with the horizontal. The height of the building from the ground level is 25m. Determine (i) where and when it will strike the ground (ii) velocity with which it strikes the ground (iii)maximum height reached by the ball above the ground level.

Homework Equations


T total = (2Vi sin(theta))/2(9.81)
Range, R= (Vi)^2 sin2(theta)/ (9.81)
There are 4 or 5 equations relevant to projectile motion, and they should all be in your textbook.

There are problems with the two equations you list here. The first equation should contain initial and final velocities, but only has the initial velocity. Also, that range equation is only valid for the projectiles launched from ground level -- not the case here.

The Attempt at a Solution


i have solve for Vx= 20cos30 = 17.32 m/s
Vy=20sin30= 10 m/s
[/QUOTE]
I would start by finding how long it takes the ball to hit the ground. Check out the equations for projectile motion, and see which can be used to find time t given the information you know about height, initial velocity, and acceleration in the y (vertical) direction.
 

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