Answer:
(a) 8Ω (b)  Ratio = Parra/P8 ohm = 1
Explanation:
Solution
Recall that,
An high-fidelity amplifier has one output for a speaker of resistance of = 8 Ω
Now,
(a) How can  two 8-Ω speakers be  arranged, when one =  4-Ω speaker, and one =12-Ω speaker
The Upper arm is : 8 ohm, 8 ohm
The Lower arm is : 12 ohm, 4 ohm
The Requirement is  = (16 x 16)/(16 + 16) = 8 ohm
(b) compare  your arrangement  power output of with the power output of a single 8-Ω speaker
The Ratio = Parra/P8 ohm = 1
 
        
             
        
        
        
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Answer:
C. 30.6m
Explanation:
To find the height of the tower, we are to use Newtons law of motion to solve this problem. Since the penny is falling from the top of the tower, it is acted by the acceleration due to gravity. The formula to be used is:

Where H is the height of the tower, t is the time taken to hit the ground, u is the initial velocity and g is the acceleration due to gravity. 
Given that, t = 2.5 s, g =9.8 m/s², u = 0 m/s (at the top of tower)
