Answer:
f = 692 N
Explanation:
given data:
f =800N
a =1.2 m s^{2}
m= 90 kg
from newton's second law
net force [tex]F_{net} =\sum F = F_1 +F_2 +..... = ma[/tex]
therefore we have from above equation[tex]F_{net} = F -f = ma[/tex]
ma =F - f
putting all value to get force of friction
1.2*90 = 800 - f
f = 692 N