How hard would he have to pull on the couch at a 25 degree angle to lift it off the ground?

Question

Jack pulls a couch of mass 38 kg across his apartment . He pulls on the couch at an angle of 25 degrees with a force of 300 N.

 

Can someone tell me what formula to use and how I would go about answering this question?

Answer 1

The vertical component of his force is:

 

N = F sin 25°

 

This has to counter the weight of the couch before any additional force results in lifting the couch.

 

F sin 25° = mg

 

F = mg/sin 25° = (38 kg)(9.81 m/s²)/(0.423) = 882 N

 

So 300 N is not enough