To move a crate across a rough floor, you pull on it at an angle of 21 degrees above the horizontal. How much force is needed if the mass of the crate is 32kg and the coefficient of static friction between the crate and floor is 0.57

Question

To move a crate across a rough floor, you pull on it at an angle of 21 degrees above the horizontal.  How much force is needed if the mass of the crate is 32kg and the coefficient of static friction between the crate and floor is 0.57

Elena · Answer

F•cosα=Ffriction=k•mg F=kmg/cosα=0.57•32•9,8/cos 21 =191 N

Kyle · Answer

Mastering Physics said the answer is 240N. NO IDEA HOW