Average and Instantaneous Velocities •Example: A cheetah is crouched 20 m to the east of an observer. At time t=0 the cheetah begins to run due east toward an antelope that is 50m to the east of the observer. During the first 2.0s of the attack, the cheetah's coordinate x varies with time according to the equation: x=20m+(5.0m/s²)t² (a) Find the cheetah's displacement between t? = 1.0s and t?=2.0s. (b) Find its average velocity during that interval. (c) Derive an expression for the cheetah's instantaneous velocity as a function of time, and use it to find vx at t=1.0s and t = 2.0s.
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