Conservation of Energy (answer in Netwons)

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SUMMARY

The discussion centers on calculating the force exerted by a rocket pack on Pam, who has a mass of 47.1 kg and accelerates to a speed of 59.2 m/s over a distance of 15.3 m on frictionless ice. The relevant equations include the work-energy theorem and the relationship between work, force, and displacement. The key formula derived is F*x = 1/2 mv^2, which allows for the calculation of force in Newtons. The participants clarify that potential energy (PE) and kinetic energy (KE) are not directly involved in this horizontal motion scenario.

PREREQUISITES
  • Understanding of Newton's Second Law of Motion
  • Familiarity with the work-energy theorem
  • Knowledge of kinetic energy formula (KE = 1/2 mv^2)
  • Basic grasp of force and displacement relationships
NEXT STEPS
  • Study the work-energy theorem in detail
  • Learn how to apply Newton's Second Law to various scenarios
  • Explore examples of calculating force using F*x = 1/2 mv^2
  • Investigate the implications of frictionless surfaces in physics problems
USEFUL FOR

Students and educators in physics, particularly those focusing on mechanics and energy conservation principles, as well as anyone preparing for exams involving force calculations and the work-energy theorem.

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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