# Using differentiation to find a general expression

For this task i have to use differentiation to find a general expression for the rocket's velocity as a function of time.

Q. A toy rocket has been launched straight upward. Altitude y as a function of time is given as y=bt−ct2, w b = 81 m/s , c = 4.9 m/s2 , t is time in seconds, y is in meters.

not sure how to start this question ! please help

## Answers and Replies

Chestermiller
Mentor
How is the derivative of the displacement with respect to time related to the instantaneous velocity of an object?

air79
Ray Vickson
Homework Helper
Dearly Missed
For this task i have to use differentiation to find a general expression for the rocket's velocity as a function of time.

Q. A toy rocket has been launched straight upward. Altitude y as a function of time is given as y=bt−ct2, w b = 81 m/s , c = 4.9 m/s2 , t is time in seconds, y is in meters.

not sure how to start this question ! please help

(1) You should write y = b t - c t^2 to show that the "2" next to the "t" is a power, not just a multiple.
(2) Do you know what differentiation means? Do you know how to apply differentiation to the given expression for y?
(3) Do you know why you should use differentiation in this problem?
What does your textbook say about (2) and (3)?

scottdave