A horizontal force of magnitude 36.4 N pushes a block of mass 3.80 kg across a f
ID: 1464004 • Letter: A
Question
A horizontal force of magnitude 36.4 N pushes a block of mass 3.80 kg across a floor where the coefficient of kinetic friction is 0.632. (a) How much work is done by that applied force on the block-floor system when the block slides through a displacement of 3.67 m across the floor? (b) During that displacement, the thermal energy of the block increases by 33.6 J. What is the increase in thermal energy of the floor? (c) What is the increase in the kinetic energy of the block?
I know the answers to A and C but i can not figure out C:
A ) 134 J
B) ????
C)47.2 J
Explanation / Answer
C)
When ever work is done to a system there is a transfer of energy.
Delta(W) = Delta(energy)
Delta(energy) = F*x - u*m*g*x
= (36.4x3.67)- (0.632x3.80x9.8x3.67)
=133.59- 86.38
= 47.21J
=12.86J