SOLUTION: A stone is projected vertically upwards and its height in meters after T seconds is given by h=50t-t^2. Find the time taken for the stone to first reach a height of 120meters.
I
Algebra.Com
Question 792713: A stone is projected vertically upwards and its height in meters after T seconds is given by h=50t-t^2. Find the time taken for the stone to first reach a height of 120meters.
I used the quadratic equation to find t but i didnt make it i got stuck when i used the cross method to find the factors, please help me...thankyou
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A stone is projected vertically upwards and its height in meters after T seconds is given by h=50t-t^2. Find the time taken for the stone to first reach a height of 120meters
-----------------
Solve:: 50t-t^2 = 120
-----
t^2 - 50t + 120 = 0
-----
t = [50 +- sqrt(2500-4*120)]/2
-----
t = [50 +- sqrt(2020)]/2
----
t = [50 +- 44.94]/2
-----
Smallest positive value of "t":
t = 2.5278 seconds
------------------------
Cheers,
Stan H.
===================
RELATED QUESTIONS
A stone is projected vertically upwards from the ground with an initial velocity of 79... (answered by ikleyn)
a stone is thrown vertically upwards at a speed of 24 m/s. its height h meters after t... (answered by Alan3354)
a stone is thrown vertically upwards at a speed of 24 m/s. its height h meters after t... (answered by solver91311,Alan3354)
Heey, I just can't figure out how to answer this question!
I've tried things, but then... (answered by scott8148)
A projectile is fired vertically upward and its height h in meters after t seconds is... (answered by Shin123)
When a body is projected vertically upwards with the velocity v=7m/s, the height s... (answered by rothauserc)
URGENT QUESTION NEEDED WITH @ DAYS TIME (Tank you soo much)the question is_
a ball is... (answered by Alan3354)
If a stone is tossed from the top of a 210 meter building, the height of the stone as a... (answered by Alan3354)
If a stone is tossed from the top of a 310 meter building, the height of the stone as a... (answered by nerdybill)