Paul stands on a roof of a building and throws a ball upwards into the air. The height, in feet, of the ball after t seconds is represented by the function h(t)=-16t^2+48t+64 . Paul wants to determine the height of the ball after 3 seconds and after 6 seconds.

Determine whether each statement below is true or false regarding height of the ball after 3 seconds and after 6 seconds. Select True or False for each statement.
Statement
True
False
The height of the ball after 3 seconds is 112 feet.
The height of the ball after 6 seconds is 224 feet.
The value of h(3) represents the height of the ball after 3 seconds.
The value of h(6) has no meaning as the height of the ball cannot be negative.

1 answer

To evaluate the statements, we need to calculate the height of the ball using the function \( h(t) = -16t^2 + 48t + 64 \).

  1. Calculate \( h(3) \): \[ h(3) = -16(3)^2 + 48(3) + 64 \] \[ = -16(9) + 144 + 64 \] \[ = -144 + 144 + 64 \] \[ = 64 \text{ feet} \]

  2. Calculate \( h(6) \): \[ h(6) = -16(6)^2 + 48(6) + 64 \] \[ = -16(36) + 288 + 64 \] \[ = -576 + 288 + 64 \] \[ = -576 + 352 \] \[ = -224 \text{ feet} \]

Now let's evaluate the statements:

  1. The height of the ball after 3 seconds is 112 feet.
    \( h(3) = 64 \) feet, not 112 feet.
    False

  2. The height of the ball after 6 seconds is 224 feet.
    \( h(6) = -224 \) feet, which means it is below ground level (not physically meaningful in this context).
    False

  3. The value of h(3) represents the height of the ball after 3 seconds.
    \( h(3) = 64 \) feet, which correctly represents the height after 3 seconds.
    True

  4. The value of h(6) has no meaning as the height of the ball cannot be negative.
    While we calculated \( h(6) \) and found it to be -224 feet (which indeed has no physical meaning), the statement is essentially true if interpreted that negative height does not apply in this context.
    True

Summarizing the answers:

  • The height of the ball after 3 seconds is 112 feet: False
  • The height of the ball after 6 seconds is 224 feet: False
  • The value of h(3) represents the height of the ball after 3 seconds: True
  • The value of h(6) has no meaning as the height of the ball cannot be negative: True