3. A warehouse employee is pushing a 30.0 kg desk across a floor at a
constant speed of 0.50 m/s. How much work must the employee do on
the desk to change the speed to 1.00 m/s?

Respuesta :

Answer: The employee must do 11.2308 Joules of work

Explanation:

Work done = force × distance

But  

Force = ma(mass x acceleration due to gravity)

F = 30×9.8

F = 294N

Also distance moved can be found using  the equation  

v² = u² +2gS

1.00 ² = 0.50²+2(9.8)S

1 =0.25+19.6S

1-0.25 =19.6S

0.75=19.6S

S=0.75/19.6

S = 0.0382m

Work done = force × distance = FS

Work done = 294 N X 0.0382m

Workdone =11.2308Nm = 11.2308 Joules

Work done required by the employee to do on the desk to change the speed to 1.00 m/s is 11.3 J.

What is work done?

Work done is the force applied on a body to move it over a distance. Work done by a body can be given as,

[tex]W=Fd[/tex]

Here (F) is the magnitude of force and (d) is the distance traveled.

From the second law of motion, the force is product of mass time acceleration. Thus the above formula can be given as,

[tex]W=(ma)d[/tex]

For the gravitational acceleration, it can be written as,

[tex]W=(mg)d\\W=mgd[/tex]

The constant speed by which, the warehouse employee is pushing the desk across a floor is 0.50 m/s and the the final speed of the desk is 1 m/s.

Thus, the distance traveled by it can be find out using the third law of motion as,

[tex]v^2-u^2=2gd\\1^2-0.25^2=2\times9.8\times d\\d=0.0382\rm m[/tex]

As the mass of the desk is 30 kg and the distance moved is 0.382 meters. Thus, put the values in the above formula as,

[tex]W=30\times9.81\times0.0382\\W\cong11.3\rm J[/tex]

Thus the work done required by the employee to do on the desk to change the speed to 1.00 m/s is 11.3 J.

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