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
Answer:
86
Step-by-step explanation:
In this question, we are asked to calculate the average mean score for a group of students split into two different emerging groups.
We calculate the total score for each of the groups. This is done by multiplying the average score by the number of students.
Total score of section A is 15 * 80 = 1,200
For section B, total score is 20 * 90 = 1,800
Overall score is thus 1200 + 1800 = 3000
We add the scores together and divide by the total number of students in both sections
Average score is thus 3000/35 = 85.71 which is approximately 86
Answer:
y = 
Step-by-step explanation:
The equation for a linear graph is usually written in the following format...
y = mx + b
Where m would be the slope, usually referring to rise over run and b would be the y-intercept (where the line crosses the y-axis). From the graph, we can see that the line crosses the y-axis at point 3 so b would be 3. The graph also shows us that for every 1 value that the line rises it moves to the right 2 values. Therefore, the slope would be 1/2. Using these values we can create the following equation...
y =
Answer:
45-13= 32
32/8= 4
she can buy 4 lbs ham
Step-by-step explanation:
