Find work done given time, acceleration, and mass

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SUMMARY

The discussion focuses on calculating the net work done on a box with a mass of 6.0 kg, accelerated at 2.2 m/s² for 5.9 seconds. The force exerted on the box is calculated using Newton's second law, yielding 13.2 N. To find the distance (d) traveled, participants suggest using kinematic equations, specifically the equation for distance under constant acceleration. The conversation highlights the importance of ensuring consistency between speed and distance calculations to arrive at the correct work done.

PREREQUISITES
  • Understanding of Newton's second law (F=ma)
  • Familiarity with kinematic equations for constant acceleration
  • Knowledge of the work-energy theorem
  • Basic algebra for solving equations
NEXT STEPS
  • Learn how to apply kinematic equations to find distance (d) in motion problems
  • Study the work-energy theorem and its applications in physics
  • Explore the relationship between force, mass, and acceleration in various contexts
  • Practice solving problems involving net work and mechanical energy changes
USEFUL FOR

This discussion is beneficial for physics students, educators, and anyone interested in understanding the principles of work, energy, and motion in mechanics.

daltomagne
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a box with a mass of 6.0 kg is accelerated from rest by a force across a floor at a rate of
2.2 m/s^2 for 5.9 s. Find the net work done on the box

m=6.0kg
a=2.2m/s^2
t=5.9 s
a=0 degrees

i know W=Fdcos(a)
and F=ma


so,
F=6.0kg*2.2m/s^2=13.2N
W=13.2N*d*cos0=13.2N*d

I am a little unsure as how to find d though. would it be one of the kinematic equations?
 
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hi daltomagne! :smile:

(try using the X2 icon just above the Reply box :wink:)
daltomagne said:
a box with a mass of 6.0 kg is accelerated from rest by a force across a floor at a rate of
2.2 m/s^2 for 5.9 s. Find the net work done on the box

I am a little unsure as how to find d though. would it be one of the kinematic equations?

That's right. :smile:

You can either use one of the standard constant acceleration equations to find d, or you can use another of them to find vf, and then apply the work-energy theorem ( work done = change in mechanical energy).
 
so I'm thinking v=vi+at and that gives me vi=-12.98m/s
and
xf=xi+vit+1/2at2?
but that gives me a value for x=-38.3 m?

so something isn't adding up
 
where's the contradiction? :confused:

one figure is speed, the other is distance, they should both give you the same work. :wink:
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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