What is the initial velocity of the ball on a smooth ramp?

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    Kinematics
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Discussion Overview

The discussion revolves around solving a physics problem related to the initial velocity of a ball rolling up a smooth ramp. The problem involves concepts of kinematics, including acceleration, velocity, and height, and is framed within the context of an exam exercise.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant describes a scenario where a ball is rolled up a ramp, reaching a height of 19.6 m with a final velocity of 4.9 m/s and an acceleration of -3.7 m/s².
  • Another participant proposes a formulaic approach to find the initial velocity using energy conservation principles, suggesting an initial velocity of 20 m/s.
  • There is a request for clarification on which parts of the problem are causing difficulty, indicating a need for more detailed discussion on the problem-solving process.
  • A suggestion is made to separate the problems into individual threads for better focus and assistance.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the solution to the problem, and there is no agreement on the proposed initial velocity or the methodology used to arrive at it. The discussion remains unresolved.

Contextual Notes

Participants express uncertainty about the correct approach to solving the problem, and there are unresolved aspects regarding the application of kinematic equations and energy conservation principles.

Who May Find This Useful

This discussion may be useful for students preparing for physics exams, particularly those focusing on kinematics and problem-solving strategies in physics.

Fist of Justice
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Hi, I am new to Physics. I'm having trouble solving these word problems. For the third question I need to find the time first and then the initial velocity?

1. A young girl gives her toboggan a push of 4.0 m/s up a hill. It slides up the hill slowing down at an acceleration of 8.0 m/s2 [down]. It comes to a stop and then slides back towards her speeding up at the same rate as it slowed down on the way up. If the girl has to run 48 m down the hill from where it first was pushed to get to where her sled stopped, find the elapsed time for the journey.

2. A porpoise jumps straight up and crashes back into the water at 8.9 m/s. The drag and buoyancy forces of the water slow the porpoise down with an acceleration of -9.3 m/s2 as the porpoise finally slows to a stop. Find the depth the porpoise reaches.

3. Sanna rolls a ball up to another person on a smooth ramp 19.6 m above her. The ball reaches the other person’s hands when it is traveling 4.9 m/s uphill. If the ramp angle slows the ball down by 3.7 m/s each second it travels up the ramp, find the initial velocity of the ball.
 
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What parts are you having trouble with? Start with telling us what you know or how far you've gotten. Are these homework?
 
No this is exercise for my exam, but I don't have the solutions to these questions. I've been trying to figure out these questions forever.
 
For #3, I think it's this

½mvo² = ½mv1²+mgh
vo = √(v1²+2gh) = 20 m/s

Am I right?
 
You have three problems here. Start a separate thread for each one in the introductory physics homework section (and please do use the template that appears when you start a thread there) and you'll get much better and more heful answers.
 
Locking this thread, but only so that the discussion can be restarted in the homework forums.
 

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