Conservation of Energy (answer in Netwons)

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Homework Help Overview

The problem involves a scenario where a person, Pam, uses a rocket pack on frictionless ice to accelerate from rest to a certain speed. The context is centered around the conservation of energy principles, specifically relating to kinetic and potential energy, and the calculation of force in Newtons.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the work-energy theorem and its implications for calculating the force exerted by the rocket pack. There are questions about the relationship between work, force, and displacement, as well as the need for understanding the time variable in the context of power.

Discussion Status

The discussion is ongoing, with participants exploring different aspects of the problem. Some have provided insights into relevant equations, while others express confusion about the application of these concepts. There is no explicit consensus, but several lines of reasoning are being examined.

Contextual Notes

Participants note the absence of resistance forces and the need to clarify the relationship between work done and energy changes. There is also uncertainty regarding the time duration of Pam's movement, which affects the calculations.

IBdoomed
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Pam has a mass of 47.1 kg and she is at rest on
smooth, level, frictionless ice. Pam straps on
a rocket pack. The rocket supplies a constant
force for 15.3 m and Pam acquires a speed of
59.2 m/s.
What is the magnitude of the force?
Answer in units of N
The acceleration of gravity is 9.8 m/s^2

I know the KE= 1/2 mv^2 and that PE=mgh.
I do not know how to get an answer in Newtons however..
 
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Do you know work energy theorem?
 
You also need the equation for work done by a force acting over a distance.
 
I do not! could you please explain?
 
The theorem says in absence of any Resistance force increase in total energy of a body is equal to the work done on it. Here work is done by rocket pack force.
 
and work= power/time right? so how do i solve this if i don't know how long she was moving?
 
Power is not involved at all.
work = force*displacement
 
oh sorry. well I'm pretty lost then... can you help me any more than this?
 
work done = gain in PE + gain in KE
 
Last edited:
  • #10
I surrender.
 
  • #11
F*h = mgh + 1/2 mv^2 if it is going vertically
F*x = 1/2 mv^2 if it is moving horizontally
 

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