Answer:
μ = 0.375
Explanation:
F = Applied force on the trash can = 75 N
W = weight of the trash can = 200 N
f = frictional force acting on trash can
Since the trash can moves at constant speed, force equation for the motion of can is given as
F - f = 0
75 - f = 0
f = 75 N
μ = Coefficient of friction
frictional force is given as
f = μ W
75 = μ (200)
μ = 0.375
The thermal efficiency of an engine is

where
W is the work done by the engine
Q is the heat absorbed by the engine to do the work
In this problem, the work done by the engine is W=200 J, while the heat exhausted is Q=600 J, so the efficiency of the machine is
The amount of solid does not affect how you are describing the solid so a is the answer
Answer:
Scientific Notation: 3.45 x 10^5
E Notation: 3.45e5