h(t)=−4.9t2+21t+0.8
the height of an object at time (t)
the vertical launch velocity is 21 m/s
the launch height is 0.8 m
The given expression is h(t) = -4.9t^2 + 21t + 0.8. This represents a mathematical function that describes the height (h) of an object at a given time (t) in seconds.
To find the height of the object at a specific time, substitute the value of t into the equation and calculate the result.
For example, if you want to find the height at t = 2 seconds, you would substitute t = 2 into the equation:
h(2) = -4.9(2)^2 + 21(2) + 0.8
Simplify the equation:
h(2) = -4.9(4) + 42 + 0.8
h(2) = -19.6 + 42 + 0.8
Finally, calculate the result:
h(2) ≈ 23.2
Therefore, the height of the object at t = 2 seconds is approximately 23.2 units.