Question 788873
When the pad is struck with just sufficient force to ring the bell the height h in metres of the weight r seconds after the pad is struck is given h = 8t-4.9r^2. 
a) How high is the weight 0.5 seconds after the pad is struck?
h(0.5) = 8*0.5 - 4.9(0.5)^2 = 2.775 meters.
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b) How high is the bell?
The bell could be 3 miles high. But the weight will reach its
peak when t = -b/(2a) = 8/(2*4.9) = 0.8163 seconds
When t = 0.8163 the height is 8*4 - 4.9*0.8163^2 = 28.73 ft
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Cheers,
Stan H.
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