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Emily778
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when serving in tennis a player tosses the tennis ball vertically in the . The height h of the ball after t seconds is given by the quadratic function h(t)=5t^2+7t (the height is measured in meters from the point of the toss.)
a. How high in the air does the ball go?
b. Assume that the player hits the ball on its way down when it's 0.6m above the point of the toss. For how many seconds is the ball in the air between the toss and the serve?
I've already got 7/2x(5)=7/10.7
 9 months ago
 9 months ago
Emily778 Group Title
when serving in tennis a player tosses the tennis ball vertically in the . The height h of the ball after t seconds is given by the quadratic function h(t)=5t^2+7t (the height is measured in meters from the point of the toss.) a. How high in the air does the ball go? b. Assume that the player hits the ball on its way down when it's 0.6m above the point of the toss. For how many seconds is the ball in the air between the toss and the serve? I've already got 7/2x(5)=7/10.7
 9 months ago
 9 months ago

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ranga Group TitleBest ResponseYou've already chosen the best response.0
For part a) h(t)=5t^2+7t =5(t^2  7/5t) complete the square of the expression in parenthesis to put the function in the vertex form. Then comparing it to standard vertex form: h = a(th)^2 + k where (h,k) is the vertex. Identify k and that will be how high the ball goes.
 9 months ago

Emily778 Group TitleBest ResponseYou've already chosen the best response.0
I already told you I have .7
 9 months ago

ranga Group TitleBest ResponseYou've already chosen the best response.0
First you put that under b. Secondly, that is not k. You have h.
 9 months ago

Emily778 Group TitleBest ResponseYou've already chosen the best response.0
What do I do next?
 9 months ago

ranga Group TitleBest ResponseYou've already chosen the best response.0
plug in t = .7 in h(t)=5t^2+7t and calculate h
 9 months ago

dan815 Group TitleBest ResponseYou've already chosen the best response.0
there used to be constantly questions about slopes and lines now i see these questions a lot
 9 months ago

dan815 Group TitleBest ResponseYou've already chosen the best response.0
when you throw a ball up in the air at the highest point its velocity = 0 as it is goes up going up to down, so somwhere in there it has 0 speed and velocity
 9 months ago

dan815 Group TitleBest ResponseYou've already chosen the best response.0
so h'(t) = velocity set h'(t) = 0 and solve
 9 months ago

dan815 Group TitleBest ResponseYou've already chosen the best response.0
that tells you the time it takes to get to highest veloicty then see what distance you travel given that time substituting that time into h(t)
 9 months ago

dan815 Group TitleBest ResponseYou've already chosen the best response.0
that highest point*, with 0 velocity
 9 months ago

Emily778 Group TitleBest ResponseYou've already chosen the best response.0
@ranga I got 5.145 for h. Is that right?
 9 months ago

dan815 Group TitleBest ResponseYou've already chosen the best response.0
oh is this precalc?
 9 months ago

ranga Group TitleBest ResponseYou've already chosen the best response.0
Try again. Don't forget there is a negative sign in front of t^2.
 9 months ago

ranga Group TitleBest ResponseYou've already chosen the best response.0
5t^2+7t 5(0.7)^2 + 7(.7) = ?
 9 months ago

Emily778 Group TitleBest ResponseYou've already chosen the best response.0
Now you tell me...
 9 months ago

ranga Group TitleBest ResponseYou've already chosen the best response.0
You can evaluate that using your calculator.
 9 months ago

Emily778 Group TitleBest ResponseYou've already chosen the best response.0
okay, I got 2.45?
 9 months ago

Emily778 Group TitleBest ResponseYou've already chosen the best response.0
hello?????????
 9 months ago

ranga Group TitleBest ResponseYou've already chosen the best response.0
BTW, the notifications are not working for a couple of days and so people may not be notified when tagged or a reply is posted. Yes 2.45 meters is correct for a) For b) substitute h = 0.6 in h(t) = 5t^2+7t and solve for t. You will get two values for t  the ball reaches 0.65 meters once while going up and once while coming down. Choose the higher t because they want the value when the ball is coming down.
 9 months ago
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