Explanation:
Q1) What is the speed of the tip of the minute hand of a clock where the hand is of length 7cm?
Ans1) speed, v=st=2πrT=2×227×7×10-260×60=119×10-4=1.22×10-4m/s
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<em><u>Hope it helps</u></em></h2>
 
        
             
        
        
        
Answer:
a)η = 69.18 %
b)W= 1210 J
c)P=3967.21 W
Explanation:
Given that
Q₁ = 1749 J
Q₂ = 539  J
From first law of thermodynamics 
Q₁   = Q₂ +W
W=Work out put
Q₂=Heat rejected to the cold reservoir
Q₁ =heat absorb by hot  reservoir
W= Q₁- Q₂ 
W= 1210 J
The efficiency given as



η = 69.18 %
We know that rate of work done is known as power


P=3967.21 W
 
        
             
        
        
        
that is an example of negative acceleration because it is slowing down