Answer:
a) 72.25sec
b) 6.25secs
c) after 10.5secs and 2 secs
Step-by-step explanation:
Given the height reached by the rocket expressed as;
s(t)= -4t^2 + 50t - 84
At maximum height, the velocity of the rocket is zero i.e ds/dt = 0
ds/dt = -8t + 50
0 = -8t + 50
8t = 50
t = 50/8
t = 6.25secs
Hence it will reach the maximum height after 6.25secs
To get the maximum height, you will substitute t - 6.25s into the given expression
s(t)= -4t^2 + 50t - 84
s(6.25) = -4(6.25)^2 + 50(6.25) - 84
s(6.25) = -156.25 + 312.5 - 84
s(6.25) = 72.25feet
Hence the maximum height reached by the rocket is 72.25feet
The rocket will reach the ground when s(t) = 0
Substitute into the expression
s(t)= -4t^2 + 50t - 84
0 = -4t^2 + 50t - 84
4t^2 - 50t + 84 = 0
2t^2 - 25t + 42 = 0
2t^2 - 4t - 21t + 42 = 0
2t(t-2)-21(t-2) = 0
(2t - 21) (t - 2) = 0
2t - 21 = 0 and t - 2 = 0
2t = 21 and t = 2
t = 10.5 and 2
Hence the time the rocket will reach the ground are after 10.5secs and 2 secs
The answer to your question is:
+4
-4, -3, -2, -1, 0, 1, 2, 3, 4
Answer:
+ 11m - 11
Step-by-step explanation:
6m+(m-2)(m+7)+3 = 6m + [ m*m - 14 -2m + 7m] + 3
= 6m + mm - 14 + 5m + 3
= mm + 11m - 11
6m+(m-2)(m+7)+3 = + 11m - 11
Answer:
500.
Step-by-step explanation:
The last digit must end with 0, 2, 4, 6, 8 for the Pin code to be even.
The middle 2 digits may be any numbers.
So if the last number is 0 Then there are 10*10 = 100 possible PIN codes.
So as there are 5 possible last digits , the total possible sets of digits
= 5 * 100
= 500.
Answer:
you can solve all your problems posted by this method ...
Step-by-step explanation:
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