Answer:
#see solution for details
Explanation:
-Uncertainty refers to an estimate of the amount by which a result may differ from this value,
-Precision  refers to how closely repeated measurements agree with each other.
-Accuracy refers to how closely a measured value agrees with the correct value.
-The number of significant figures is the number of digits believed to be correct by the person doing the measuring. Therefore, choosing the correct number of significant figures reduces the deviation from the point of accuracy/uncertainty or precision and thereby reducing margin of error  in the ensuing calculations.
 
        
             
        
        
        
Explanation:
Given that,
Weight of the engine used to lift a beam, W = 9800 N
Distance, d = 145 m
Work done by the engine to lift the beam is given by :
W = F d

Let W' is the work must be done to lift it 290 m. It is given by :

Hence, this is the required solution.
 
        
             
        
        
        
Answer
given,
y(x,t)= 2.20 mm cos[( 7.02 rad/m )x+( 743 rad/s )t]
length of the rope = 1.33 m
mass of the rope = 3.31 g
comparing the given equation from the general wave equation
y(x,t)= A cos[k x+ω t]
A is amplitude 
now on comparing
a) Amplitude  = 2.20 mm
b) frequency = 
      
      
            f = 118.25 Hz
c) wavelength 
         
         
         
         
d) speed 
          
          
                 v = 105.84 m/s
e) direction of the motion will be in negative x-direction
f) tension
   
   
       T = 27.87 N
g) Power transmitted by the wave
   
   
        P = 0.438 W
 
        
             
        
        
        
Answer:
a)W= - 720 J
b)ΔU= 330 J 
Explanation:
Given that
P = 0.8 atm 
We know that 1 atm = 100 KPa
P = 80 KPa
V₁ = 12 L = 0.012 m³       ( 1000 L = 1 m³)
V₂ = 3 L = 0.003 m³
Q= - 390 J ( heat is leaving from the system )
We know that work done by gas given as
W = P (V₂ -V₁ ) 
W= 80 x ( 0.003 - 0.012 ) KJ
W= - 0.72 KJ 
W= - 720 J    ( Negative sign indicates work done on the gas)
From first law of thermodynamics
Q = W + ΔU
ΔU=Change in the internal energy
Now by putting the values
- 390 = - 720 + ΔU 
ΔU= 720 - 390  J
ΔU= 330 J 
 
        
             
        
        
        
Answer:
Since steel contains iron (a magnetic metal), the magnets will attract the steel cans since aluminum is not magnetic. This is used to separate the steel cans from the aluminum cans so they can be recycled separately.