Brady throws a ball into the air. The equation
s = −16t^2 + 63t + 4
gives the height of the ball s (in feet) t seconds after throwing it. When will the ball hit the ground after he throws it?
s = −16t^2 + 63t + 4
gives the height of the ball s (in feet) t seconds after throwing it. When will the ball hit the ground after he throws it?
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We want to know when it hits the ground, so when s = 0
0 = -16t^2 + 63t + 4
Factor it:
0 = -(t-4)(16t+1)
t = 4
t = -1/16
We only want the positive time.
so after 4 seconds
0 = -16t^2 + 63t + 4
Factor it:
0 = -(t-4)(16t+1)
t = 4
t = -1/16
We only want the positive time.
so after 4 seconds
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Pull out the negative from the whole equation:
s = -(16t^2-63t-4)
Since 16*-4+1=-63, your factoring would be :
s = -(16t+1)(t-4)
Since you height s, is at 0, put s=0
0= -(16t+1)(t-4)
t= -1/16 or t=4,
since you cannot have the negative time, t= -1/16 is dismissable, thus, the time when the ball will hit the ground is t=4s
s = -(16t^2-63t-4)
Since 16*-4+1=-63, your factoring would be :
s = -(16t+1)(t-4)
Since you height s, is at 0, put s=0
0= -(16t+1)(t-4)
t= -1/16 or t=4,
since you cannot have the negative time, t= -1/16 is dismissable, thus, the time when the ball will hit the ground is t=4s
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Plug t into the equation and solve for s. That should give you the correct answer, assuming you performed the order of operations correctly. If you give me the numbers, I can gladly solve the problem for you.