a rocket rises 30 feet after one second, 85 feet after two seconds, and 140 feet after three seconds. if it continues to rise at this rate, how many feet will it rises after 16 seconds?
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After 16 seconds the rocket will rise 855 feet
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S = ut + 0.5at^2
After one second
30 = u + 0.5a
Multiply both sides with 2
60 = 2u + a ——(1)
After 2s
85 = 2u + 2a ——(2)
Equation (1) - Equation (2)
60 - 80 = 2u + a - 2u - 2a
-20 = -a
a = 20 ft/s^2
Substitute a = 20ft/s^2 in Equation (1)
60 = 2u + 20
u = 20 ft/s
After 16s
S = ut + 0.5at^2
S = 16*20 + 0.5*20*16^2
S = 2880 ft
It will rise 2880ft after 16s
After one second
30 = u + 0.5a
Multiply both sides with 2
60 = 2u + a ——(1)
After 2s
85 = 2u + 2a ——(2)
Equation (1) - Equation (2)
60 - 80 = 2u + a - 2u - 2a
-20 = -a
a = 20 ft/s^2
Substitute a = 20ft/s^2 in Equation (1)
60 = 2u + 20
u = 20 ft/s
After 16s
S = ut + 0.5at^2
S = 16*20 + 0.5*20*16^2
S = 2880 ft
It will rise 2880ft after 16s
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