Posted by tiffany on .
Your groceries are in a bag with paper handles. The handles will tear off if a force greater than 59 N is applied to them.
(a) What is the greatest mass of groceries that can be lifted safely with this bag, given that the bag is raised with constant speed? kg
(b) What if it is raised with an acceleration of 1.25 m/s2? kg

physics 
Gregorius,
Well tiffany, you use this equasion: F=ma+mg. Manipulate the formula to get mass (which is the unknown here) on one side:
f= ma+mg
FACTOR m
f=m(a+g)
DIVIDE BOTH SIDES BY (a+g)
f/(a+g)=m
This can be used for both parts of the equasion. (remember that g=9.81 m/s^2.)
a)Since the bag is lifted with constant acceleration, "a" can be ignored. So:
f/g=m m=59/9.81= 6.01kg
b)for this part just don't ignore the acceleration. plug 1.25m/s into the formula.
m=f/(a+g) m=59/(1.25+9.81)= 5.33kg