another physics problem that i dont understnad..

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An 58.0 N box of clothes is pulled 5.2 m up a 30.0° ramp by a force of 95 N that points along the ramp. If the coefficient of kinetic friction between the box and the ramp is 0.22, calculate the change in the box's kinetic energy.

• another physics problem that i dont understnad.. -

The work done by the applied force is 95 x 5.2 = 494 J

Part of the work was done overcoming the friction force. The friction force is
Ff = 58*0.22*cos30 = 11.05 N and the work done against that force is 57.5 J

The work done increasing the gravitational potential energy is:
M*g*5.2*sin 30 = 150.8 J

That leaves a total of 494 - 57.5 - 150.8 J avaialbkle to increase kinetic energy

• another physics problem that i dont understnad.. -

your awesome! but where did you get the 95 in the first equation?

• another physics problem that i dont understnad.. -

95 N is the pulling force, which they tell you. That multiplied bhy the distance pulled is the work done by that force.

Thanks for the kind words; you'd better check my numbers anyway.

• another physics problem that i dont understnad.. -

oh haha! sorry didn't see it

• another physics problem that i dont understnad.. -

uhm where did you get 57.5? and what is M & g????

• another physics problem that i dont understnad.. -

An 70.0 N box of clothes is pulled 24.0 m up a 30.0° ramp by a force of 115 N that points along the ramp. If the coefficient of kinetic friction between the box and ramp is 0.22, calculate the change in the box's kinetic energy.