Need help finding the equation to solve this Physic problems. I'll give 5 stars to anyone that can find it.

A 29 kg box initially at rest is pushed 4.53 m along a rough, horizontal floor with a constant applied horizontal force of 138.552 N. The acceleration of gravity is 9.8 m/s^2.





1)If the coefficient of friction between box and floor is 0.446, find the work done by the applied force.


2)Find the work done by the friction.


3)Find the change in kinetic energy of the box.


4)Find the final speed of the box

Need help finding the equation to solve this Physic problems. I'll give 5 stars to anyone that can find it.
Draw a free body diagram. You have the box with the weight =mass * Gravity. Normal force (Fn) equal and opposite the weight (in other words pointing straight up). You have the horizontal force to the right =to 138.55 N, and the force of friction. Remember the force of friction (Ff)=Fn*coeffcient of friction, or in this case .446*29kg *9.8 m/s^2 =126.75 N.





Now, you can go about the work a couple of ways. First find the work done if there was no friction (the applied force alone). Remember Work=F * D. Without the friction, the work would be 138.55N* 4.53m=627.63 Nm or J





The work friction does would be in the opposite direction (remember friction always opposes the direction of the applied force) The work to overcome friction would be 126.75N * 4.53 m=574.17 Nm. Depending on what level class you are taking, you might need to worry about signs or directions.





Now, the net work would be 627.63-574.18=53.454J





Remember Kinetic energy is measured in Joules, which we now have. Initial KE was 0 because there was no motion.





So, Final KE-Initial KE=Final KE (The final kinetic energy is what you calculated for net work)





Remember KE=(1/2)mV^2





To find the final speed of the box, we know the final KE 53.454 J and mass=29 kg.





53.454 J=.5*29*v^2


So, 3.68 = V^2


V=1.92 m/s





I worked this off the top of my head in a hurry, but should be correct.
Reply:man i wish answers was around when I was in school.





haha
Reply:1. Work = Force x Distance


2. work = mew ( mg)


3. Delta KE = delta work = net work


4. work = 1/2 mv^2





Hope that helps.