Solve PCAT Physics Problem: Lawn Mower Force & Acceleration in 2.5s

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SUMMARY

The discussion focuses on solving a physics problem involving a 14kg lawn mower pushed with an 88N force at a 45-degree angle. Key calculations include determining the horizontal friction force, the normal force exerted by the ground, and the force required to accelerate the mower from rest to 1.5m/s in 2.5 seconds. The relevant equations include F=ma for net forces and Vf=Vi+at for linear acceleration. Participants emphasize the importance of understanding the free-body diagram and the forces acting on the mower.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Familiarity with free-body diagrams
  • Knowledge of linear acceleration equations
  • Basic principles of friction and normal force
NEXT STEPS
  • Study free-body diagram construction for various forces
  • Learn how to calculate friction forces in different scenarios
  • Explore the application of Newton's second law in real-world problems
  • Practice solving linear acceleration problems using Vf=Vi+at
USEFUL FOR

Students preparing for the PCAT, particularly those focusing on physics concepts, as well as anyone needing a refresher on mechanics and force calculations.

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A person pushes a 14kg lawn mover at constant sped with a force of 88N directed along the handle, which is at an angle of 45 degress to the horizontal. (a) draw the Free-body diagram showing all forces acting on the mower. (b) Calculate the horizontal friction force on the mower, then (c) the normal force exerted vertically upward on the mower by the ground. (d) What force must the person exert on the lawn mower accelerate it from rest to 1.5m/s in 2.5 seconds, assuming the same friction force?

This is a problem on my practice PCAT test for Pharmacy school. And its been a while since I have had physics so any help would be appreciated.

Thanks
 
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well here are some eqns to consider,

F=ma therefore if an object isn't accelerating the net forces are zero.
The "normal" force is the one from the Earth pushing upwards on the mower; from the above comment, if the mower isn't burrowing underground, the Normal force must then equal the weight of the mower plus whatever part of the push is directed vertically.

Vf=Vi+at (linear acceleration, relating time, initial and final velocities)

PS: I sympathize, I am myself brushing the rust off of 20 years of non-use since school. Sort of like riding a bike, but more like riding one with a blindfold, as I have had to reaquaint myself with all the tricks that were once second nature. Can be done, just in the future try to figure out what eqns might be relevant and some reasoning as to which ones might be most useful. You'll get a lot more help that way.
 

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