ElizaE
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Two balls are launched in the air at the same time. One ball is launched at 40 feet per second while the other is launched at 20 feet per second, but starts 10 feet off the ground. How high does each ball go, and which goes higher? Remember, acceleration due to gravity is 32 feet per second^2 and the general equation for the height off the ground as a function of time is f(t)=-1/2at ^ 2 + v0t + c where a is acceleration due to gravity, v0 is initial velocity, c is height off the ground and f(t) is height off the ground as a function of time.

Please explain how to do this if you can, thank you!!

Respuesta :

Answer:

Comparing the heights, the first ball reaches higher, reaching 25 feet compared to the second ball's 16.25 feet.

Step-by-step explanation:

To find out how high each ball goes, we can use the equation for the height off the ground as a function of time:

[tex]\[ f(t) = -\frac{1}{2}at^2 + v_0t + c \][/tex]

Where:

[tex]- \( a \) is the acceleration due to gravity (32 feet per second\(^2\))[/tex]

[tex]- \( v_0 \) is the initial velocity[/tex]

[tex]- \( c \) is the initial height off the ground (which is 10 feet for one ball and 0 for the other)[/tex]

Let's calculate the height each ball reaches:

For the first ball (launched at 40 feet per second):

[tex]- \( v_0 = 40 \) feet per second[/tex]

[tex]- \( c = 0 \) (since it starts from the ground)[/tex]

[tex]\[ f(t) = -\frac{1}{2}(32)t^2 + (40)t + 0 \][/tex]

[tex]\[ f(t) = -16t^2 + 40t \][/tex]

To find the maximum height, we can use the vertex formula: [tex]\( t = -\frac{b}{2a} \)[/tex]

[tex]\[ t = -\frac{40}{2(-16)} = \frac{40}{32} = 1.25 \text{ seconds} \][/tex]

Now, plug [tex]\( t = 1.25 \)[/tex] into the equation to find the maximum height:

[tex]\[ f(1.25) = -16(1.25)^2 + 40(1.25) \][/tex]

[tex]\[ f(1.25) = -16(1.5625) + 50 \][/tex]

[tex]\[ f(1.25) = -25 + 50 = 25 \text{ feet} \][/tex]

So, the first ball reaches a height of 25 feet.

For the second ball (launched at 20 feet per second and starting 10 feet off the ground):

[tex]- \( v_0 = 20 \) feet per second[/tex]

[tex]- \( c = 10 \) feet (it starts 10 feet off the ground)[/tex]

[tex]\[ f(t) = -\frac{1}{2}(32)t^2 + (20)t + 10 \][/tex]

[tex]\[ f(t) = -16t^2 + 20t + 10 \][/tex]

Using the vertex formula again:

[tex]\[ t = -\frac{b}{2a} = -\frac{20}{2(-16)} = \frac{20}{32} = 0.625 \text{ seconds} \][/tex]

Now, plug \( t = 0.625 \) into the equation to find the maximum height:

[tex]\[ f(0.625) = -16(0.625)^2 + 20(0.625) + 10 \][/tex]

[tex]\[ f(0.625) = -16(0.390625) + 12.5 + 10 \][/tex]

[tex]\[ f(0.625) = -6.25 + 22.5 = 16.25 \text{ feet} \][/tex]

So, the second ball reaches a height of 16.25 feet.

Comparing the heights, the first ball reaches higher, reaching 25 feet compared to the second ball's 16.25 feet.