MHB Yes, you are correct for both parts (A) and (B)!

  • Thread starter Thread starter mathdad
  • Start date Start date
  • Tags Tags
    Application Ball
AI Thread Summary
The height of a ball thrown upward is modeled by the equation h = -16t^2 + 96t. To determine how long it takes for the ball to drop, set h to 0 and solve for t. For the height to be 80 feet, set h to 80 and solve for t, which yields two solutions due to the ball's upward and downward paths. This dual solution occurs because the ball reaches 80 feet on its way up and again on its way down. The discussion confirms the correct approach for solving both parts of the problem.
mathdad
Messages
1,280
Reaction score
0
A ball is thrown straight upward. Suppose that the height of the ball at time t is h = -16t^2 + 96t, where h is in feet and t is in seconds, with t = 0 corresponding to the instant that the ball is first tossed.

(A) How long does it take for the ball to drop?

(B) At what time is the height 80 feet? Question (B) has two answers. Why?

To answer part (A), do I set h = 0 and solve for t?

To answer part (B), do I set h = 80 and solve for t?
 
Mathematics news on Phys.org
RTCNTC said:
To answer part (A), do I set h = 0 and solve for t?

Yes.

RTCNTC said:
To answer part (B), do I set h = 80 and solve for t?

Yes.
 
Good to know that I am right.
 

Thread 'Trigonometry problem of interest'

Seemingly by some mathematical coincidence, a hexagon of sides 2,2,7,7, 11, and 11 can be inscribed in a circle of radius 7. The other day I saw a math problem on line, which they said came from a Polish Olympiad, where you compute the length x of the 3rd side which is the same as the radius, so that the sides of length 2,x, and 11 are inscribed on the arc of a semi-circle. The law of cosines applied twice gives the answer for x of exactly 7, but the arithmetic is so complex that the...
View full post »
Thread 'Unit Circle Double Angle Derivations'

Thread 'Unit Circle Double Angle Derivations'

Here I made a terrible mistake of assuming this to be an equilateral triangle and set 2sinx=1 => x=pi/6. Although this did derive the double angle formulas it also led into a terrible mess trying to find all the combinations of sides. I must have been tired and just assumed 6x=180 and 2sinx=1. By that time, I was so mindset that I nearly scolded a person for even saying 90-x. I wonder if this is a case of biased observation that seeks to dis credit me like Jesus of Nazareth since in reality...
View full post »

Thread 'Fermat's Last Theorem'

Fermat's Last Theorem has long been one of the most famous mathematical problems, and is now one of the most famous theorems. It simply states that the equation $$ a^n+b^n=c^n $$ has no solutions with positive integers if ##n>2.## It was named after Pierre de Fermat (1607-1665). The problem itself stems from the book Arithmetica by Diophantus of Alexandria. It gained popularity because Fermat noted in his copy "Cubum autem in duos cubos, aut quadratoquadratum in duos quadratoquadratos, et...
View full post »

Similar threads

MHB Calculating Ball Height and Time with Quadratic Formula
Replies
4
Views
2K
MHB Two Balls Thrown Vertical Upward
Replies
36
Views
7K
B Solving equations but getting an identity - what mistakes were made?
Replies
4
Views
932
MHB Application of quadratic function in kinematics
Replies
1
Views
2K
MHB Non-linear function with two unknown constants and one variable
Replies
7
Views
3K
MHB Correctness of Ball-Dropping Problem Answer
Replies
3
Views
3K
MHB Finding Time for a Kicked Ball
Replies
5
Views
3K
Two balls, dropped with a delay of ##\Delta t##, meet after rebound
Replies
34
Views
2K
MHB Jaden Harris' Velocity Ques. at Yahoo Answers
Replies
1
Views
4K
Distance-time graph of a ball throw vertically up from a fixed point
Replies
5
Views
2K

Hot Threads

Recent Insights

Back
Top