How Do You Calculate the Movement of a Push Lawn Mower?

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Homework Help Overview

The discussion revolves around the mechanics of a push lawn mower, specifically analyzing forces acting on it while in motion. The problem involves calculating the normal force, assessing the mower's movement at a constant speed, and determining the distance traveled over a set time period.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants explore the calculation of the normal force by considering both the applied force and the weight of the mower. There are questions about whether the initial calculations account for all forces acting on the mower.
  • Some participants question the assumptions made regarding the forces and the conditions for constant speed, particularly in relation to friction.
  • There is an inquiry into the net force acting on the mower and how it relates to the acceleration and motion equations.

Discussion Status

The discussion is ongoing, with participants providing insights and prompting further exploration of the forces involved. Some guidance has been offered regarding the need to consider all forces acting on the mower, including friction and weight, but no consensus has been reached on the correctness of the initial calculations.

Contextual Notes

Participants are working under the constraints of a homework assignment, which may limit the information available and the methods they can use to solve the problem. There is an emphasis on understanding the forces involved rather than simply arriving at a solution.

drunkencharms
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Homework Statement


A person starts to mow a lawn with 50kg old fashioned push lawn mower. The handle of the mower makes an angle of 45 degrees with the sure of the lawn. A 200 N force is applied along the handle of the mower by the person
a. Determine the normal force exerted by the ground on the mower
b. If u=0.2, determine if the mower moves with a constant speed.
c.How far the mower will travel if the person pushes it for 1min along the staright line?

Homework Equations

The Attempt at a Solution


a) Fnormal = 200Nsin45 = 141

b) F=uFnormal (.2)(141) = 28.2
141-28.2
=112.8
F = ma
112 / 50
a = 2.24
c. ?

Not sure if a or b are correct
 
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drunkencharms said:
a) Fnormal = 200Nsin45 = 141

This (with a unit added in the end) is only accounting for the force necessary to counteract the push that the person exerts on the handle. The lawnmower also has a weight (assuming non-zero gravity).
 
drunkencharms said:

Homework Statement


A person starts to mow a lawn with 50kg old fashioned push lawn mower. The handle of the mower makes an angle of 45 degrees with the sure of the lawn. A 200 N force is applied along the handle of the mower by the person
a. Determine the normal force exerted by the ground on the mower
b. If u=0.2, determine if the mower moves with a constant speed.
c.How far the mower will travel if the person pushes it for 1min along the staright line?

Homework Equations

The Attempt at a Solution


a) Fnormal = 200Nsin45 = 141

Is this the only force applied to the ground by the mower?

b) F=uFnormal (.2)(141) = 28.2
141-28.2
=112.8
F = ma
112 / 50
a = 2.24
c. ?

Not sure if a or b are correct
 
drunkencharms said:
a. Determine the normal force exerted by the ground on the mower
You have the vertical component of the applied force + the weight [Mg] , so what is Fn.
drunkencharms said:
b. If u=0.2, determine if the mower moves with a constant speed.
Use Newton Second Law
$$F_{net}=Ma$$
Think about the net force , what will it be?
Note that there is no motion along the y-axis and don't forget to take the frication into account.
What is your equation along the x-axis?
drunkencharms said:
c.How far the mower will travel if the person pushes it for 1min along the staright line?
Use the linear motion laws [after getting 'a' from the previous part ]
 

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