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

In summary: Time is given as 1 min or 60 sec. Therefore, the mower will travel 60 times the distance calculated in the previous part.
  • #1
drunkencharms
1
0

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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  • #2
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).
 
  • #3
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
 
  • #4
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 ]
 
  • #5
, please double check and let me know if you have any questions. Regarding part c, we can use the equation d = vt, where d is the distance traveled, v is the velocity, and t is the time. We can find the velocity using the equation v = u + at, where u is the initial velocity (which we assume is 0 since the mower starts from rest) and a is the acceleration calculated in part b. So, v = 0 + (2.24)(60) = 134.4 m/s. Then, we can plug this into the first equation to find the distance traveled: d = (134.4)(1) = 134.4 meters. Therefore, the mower will travel 134.4 meters in 1 minute if pushed in a straight line.
 

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

1. What is work?

Work is defined as the transfer of energy from one object to another by applying a force over a distance. It is typically measured in joules (J) and can be positive or negative depending on the direction of the force and the displacement of the object.

2. How is work calculated?

Work is calculated by multiplying the force applied to an object by the distance the object moves in the direction of the force. The formula for work is W = Fd, where W is work, F is force, and d is distance.

3. What is the relationship between work and energy?

Work and energy are closely related concepts. Work is the transfer of energy, meaning that when work is done on an object, energy is transferred to that object. Similarly, when an object does work, it uses energy to do so.

4. How is power related to work and energy?

Power is the rate at which work is done or energy is transferred. It is calculated by dividing work by time, or P = W/t. Therefore, the more work or energy that is transferred in a given amount of time, the greater the power.

5. What are some examples of work and energy in everyday life?

Some examples of work and energy in everyday life include lifting objects, running, and using electrical appliances. Whenever a force is applied to move an object or cause a change in its position or state, work is being done and energy is being transferred.

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