Projectile Motion ball is thrown upward

Click For Summary

Homework Help Overview

The problem involves projectile motion, specifically analyzing the trajectory of a ball thrown upward at an angle of 30° to the horizontal, which lands on a building 20 m away and 5.0 m above the throwing point. The goal is to determine the initial velocity of the ball.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the lack of given initial velocity and explore which equations might be applicable with only one unknown. Some question the assumption that the ledge coincides with the apex of the projectile's path, while others clarify the need to consider gravitational acceleration.

Discussion Status

The discussion is ongoing, with participants offering guidance on focusing on the vertical component of the launch velocity and questioning assumptions about the projectile's path. There is no explicit consensus, as multiple interpretations of the problem are being explored.

Contextual Notes

Participants note the absence of certain values, such as gravitational acceleration, and discuss the implications of the problem's setup on the analysis.

creynaud
Messages
4
Reaction score
0

Homework Statement


A ball is thrown upward at an angle of 30° to the horizontal and lands on the top edge of a building that is 20 m away. The top edge is 5.0 m above the throwing point. How fast was the ball thrown?

Homework Equations


xcos30
ysin30

The Attempt at a Solution


Im not sure what I am supposed to do considering there is no velocity given
 
Physics news on Phys.org
creynaud said:
Im not sure what I am supposed to do considering there is no velocity given
creynaud said:
How fast was the ball thrown?
Well, the problem is asking for the initial velocity, so its very natural that the initial velocity is not given to you!

Just take a look at the equations you have at hand and see which one has only one unknown, taking into account the data given in the problem.
 
So the ledge coincides with the apex of the parabola
You also need the value for g (gravitational acceleration)
Youll be working on the vertical vector of the launch velocity first
 
dean barry said:
So the ledge coincides with the apex of the parabola
Not necessarily. The projectile can land at the given spot after passing through its zenith.

Fig1.gif
 
dean barry said:
So the ledge coincides with the apex of the parabola
You also need the value for g (gravitational acceleration)
Youll be working on the vertical vector of the launch velocity first
This assumption is not implied by the text and is not necessary.
 
Beyond me, sorry.
Dean
 

Similar threads

A ball is thrown w/initial speed vi at an angle 𝜃i with the horizontal
  • · Replies 5 ·
Replies
5
Views
2K
Solving a Ball Thrown off a Cliff: How Long Does it Take?
  • · Replies 4 ·
Replies
4
Views
2K
Projectile Motion Soccer Ball Problem
  • · Replies 22 ·
Replies
22
Views
5K
Projectile Motion Experimental Error
  • · Replies 1 ·
Replies
1
Views
2K
Projectile Motion Graph Analysis
  • · Replies 1 ·
Replies
1
Views
2K
Projectile motion: Two Balls and Building
  • · Replies 9 ·
Replies
9
Views
2K
Ball is thrown at the edge of the roof of a building
  • · Replies 31 ·
2
Replies
31
Views
4K
Relative motion/Projectile motion
  • · Replies 18 ·
Replies
18
Views
5K
Laws of motion and a projectile thrown from an accelerating elevator car
  • · Replies 13 ·
Replies
13
Views
2K
Air resistnce in projectile motion decreasing time of flight
  • · Replies 1 ·
Replies
1
Views
3K