What is the mass

Question

A teacher pushes a desk with 22 N of force to the right. A student helps by pushing the desk with 16 N of force in the same direction. Draw a FBD. If the desk accelerates at a
constant rate of 0.4 m/s2, what is the mass of the desk?

Answer 1

Net force to the right (positive direction):

 

F = (22 + 16) N = 38 N

 

By Newton's 2nd law,

 

m = F/a = (38 N) / (0.4 m/s²) = 95 kg