105.57 joule t is work done in friction joures
work done=f×s
f= force
s= distance
m= mass
v^2-u^2=2as
25=2×6.9×a
a=25/13.8
a=1.8 m/s^2
work done=f×s
work done=ma×s
work done= 8.5 kg×1.8 m/s^2× 6.9 m
work done=105.57 joule
When an item is moved across a distance by an external force, at least a portion of that force must be applied in the direction of the displacement. This is known as work done in physics. By multiplying the length of the path by the component of the force operating along the path, work may be calculated if the force is constant. The work W is equal to the force f times the distance h, or W = mgh, to mathematically describe this idea. The work is W = mas if the force is applied at an angle of to the displacement.
To know more about work done visit : brainly.com/question/10334435
#SPJ4