quadratic problem help

[Maryee]

A T-ball player hits a ball from a tee that is 2m tall. The height of the ball at a given time is modelled by the function h(t) = -5t^2 +40t +2, where heighth(t), is in metres and time is in seconds.
What will the height be after 1 second?
a) h(t) = -5t^2 +40t +2
= 5-(1) +40(1) +2
= -5+40+2
= 37

b) when will the ball hit the ground?

How do u do this part please I am having trouble

 

[Mrspi]

A T-ball player hits a ball from a tee that is 2m tall. The height of the ball at a given time is modelled by the function h(t) = -5t^2 +40t +2, where heighth(t), is in metres and time is in seconds.
What will the height be after 1 second?
a) h(t) = -5t^2 +40t +2
= 5-(1) +40(1) +2
= -5+40+2
= 37

b) when will the ball hit the ground?

How do u do this part please I am having trouble

When the ball hits the ground, the height h(t) will be 0:

$\displaystyle h(t) = -5t^2 + 40t + 2$

$\displaystyle 0 = -5t^2 + 40t + 2$

Solve that quadratic equation for t. Be sure to check your answer(s); remember that a negative value for t does not make sense here, since the time in seconds cannot be less than 0.

 

[Shoppingal]

When the ball hits the ground, the height h(t) will be 0:

$\displaystyle h(t) = -5t^2 + 40t + 2$

$\displaystyle 0 = -5t^2 + 40t + 2$

Solve that quadratic equation for t. Be sure to check your answer(s); remember that a negative value for t does not make sense here, since the time in seconds cannot be less than 0.

so now you subsitute 0 into the equation an 0= -5t^2 +40t +2
= -5(0) + 40(0) +2
= 2

so the ball hits the ground in 2seconds?