# Another Basic Force Problem

1. Feb 14, 2006

### mb85

A 1800 kg jet engine is fastened to the fuselage of a passenger jet by just three bolts (this is the usual practice). Assume that each bolt supports one-third of the load. (a) Calculate the force on each bolt as the plane waits in line for clearance to take off. (b) During flight, the plane encounters turbulence, which suddenly imparts an upward vertical acceleration of 2.2 m/s2 to the plane. Calculate the force on each bolt now.

I figured the equation to use for part A would be,
F=m(a+g)
= 1800(9.8+0)
=17640 then x 1/3rd
= 5880 N for each bolt

For part B, same equation with addition of the new acceleration
F=m(g - a)
=1800(9.8 - 2.2)
= 10640 then x 1/3rd
= 3546.7 N

I think im missing some basic concept or understanding of what i am exactly looking for? and what the equation should actually be.

2. Feb 14, 2006

### Andrew Mason

Your answer to a) is correct. In b) your approach is correct but: ask yourself what the direction of the force on the engine is if the wings are forced upward with an acceleration of 2.2 m/sec^2. Does that add or reduce tensile forces on the bolts?

AM

Last edited: Feb 14, 2006