Calculus  average velocity
posted by B <3 .
*VELOCITY OF A CAR* Suppose the distance s (in feet) covered by a car moving along a straight road after t sec is given by the function s = f(t) = 2t^2 + 48t.
a. Calculate the average velocity of the car over the time intervals [20,21], [20, 20, 20.1], and [20, 20.01].
b. Calculate the (instantaneous) velocity of the car when t = 20.
c. Compare the results of part (a) with that of part (b).
*Can someone please help me? I have been trying to do my homework for some time now and I am stuck on this problem. I tried to work it out, but I did not understand what to substitute in for “t”. I used the average velocity formula and did f(t+h)f(t) divided by h …. And I got: 4t + 48. Somehow, I think this is way wrong! Can you tell me where I went wrong here and how to do this problem!?? Pleaseee!
any help would be great!!! :)

The instantaneous velocity is indeed 4t+48
However, the average velocity is the average of the instaneous velocties at two times. Example, in a, times 20,and times 20.1
v(20)=4t+48=128
v(20.1)=128.4
average: 128.2 
do you have the dike too?
Respond to this Question
Similar Questions

physics college
An antelope moving with constant acceleration covers the distance between two points 70.0 m apart in 7.00 s. Its speed as it passes the second point is 15.0 m/s. (a) What is its speed at the first point? 
physics
A car is stopped at a traffic light. It then travels along a straight road so that its distance from the light is given by x(t) = bt2 – ct3, where b = 2.40m/s2 and c = 0.120m/s3. (a) Calculate the average velocity of the car for … 
Physics
A car is stopped at a traffic light. It then travels along a straight road so that its distance from the light is given by x(t) = bt2  ct3, where b = 2.60 m/s2 and c = 0.150 m/s3. (a) Calculate the average velocity of the car for … 
physics
A car starts from rest and accelerates uniformly along a straight horizontal road at 3 metres second squeared for 4 seconds,after which it continues with a constant velocity for a further 6 seconds.CALCULATE THE MAGNITUDE OF THE MAXIMUM … 
Physical Science
A car starts from rest and accelerates uniformly along a straight horizontal road at 3 metres second squeared for 4 seconds,after which it continues with a constant velocity for a further 6 seconds.What is the magnitude of the maximum … 
physics
A man on the top of a 40 meter tower directly overhead the road is watching a car moving on a straight road. The car speed makes an angular velocity with respect to the observer in a constant speed of 0.16radian/sec. Find the linear … 
Math
A car moves along a straight road in such a way that its velocity (in feet per second) at any time t (in seconds) is given by v(t) = 3t sqrt(64−t^2) (0 ≤ t ≤ 8). Find the distance traveled by the car in the 8 sec … 
physics
A Honda Civic travels in a straight line along a road. Its distance x from a stop sign is given as a function of time t by the equation x(t)= α t2− β t3, where α = 1.43m/s2 and β = 4.60×10−2m/s3 . 1)Calculate … 
Physics
A Honda Civic travels in a straight line along a road. Its distance x from a stop sign is given as a function of time t by the equation x(t)= α t2− β t3, where α = 1.40m/s2 and β = 5.05×10−2m/s3 A) … 
Math 160
The position function of an object moving along a straight line is given by s = f(t). The average velocity of the object over the time interval [a, b] is the average rate of change of f over [a, b]; its (instantaneous) velocity at …