Solving a Physics Problem: Net Work Done on a Box

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SUMMARY

The discussion focuses on calculating the net work done on a box with a mass of 5.0 kg, accelerated at 2.0 m/s² for 7.0 seconds. The user initially misapplied the formula for work by incorrectly using displacement as velocity multiplied by time. The correct approach involves using the kinematic equation to find displacement under constant acceleration. The final calculation reveals that the net work done on the box is 490 Joules.

PREREQUISITES
  • Understanding of Newton's Second Law (f = ma)
  • Familiarity with the work-energy principle (w = fdcostheta)
  • Knowledge of kinematic equations for constant acceleration
  • Basic algebra skills for manipulating equations
NEXT STEPS
  • Study kinematic equations for constant acceleration
  • Learn about the work-energy theorem in physics
  • Practice problems involving net work and displacement
  • Explore applications of Newton's laws in real-world scenarios
USEFUL FOR

Students studying physics, particularly those focusing on mechanics, as well as educators looking for examples of work and energy calculations in a classroom setting.

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Homework Statement


a box of mass 5.0 kg is accelerated from rest across a floor at a rate of 2.0m/s^2 for 7.0s. find the net work done on the box.


Homework Equations


f = ma
w= fdcostheta

The Attempt at a Solution


f = ma
f=10

w = fdcostheta
w=10d
w=10*v*t
w=10*v*7
w=10*a*t*7
w = 10*14*7
w=980

the answer is 490...

need help... what am i doing wrong
 
Physics news on Phys.org
You set the displacement equal to vt. That is incorrect. You will need to use the correct kinematic equation for objects traveling with constant acceleration, to find the displacement.
 
thank you!

i got it!
 

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