Question

Posted by Aletha on Sunday, March 18, 2007 at 6:51pm.

After t hours of an 8-hour trip the distance a car travels is modeled by:
D(t)= 10t + (5)/(1+t) - 5
where D(t) is measured in meters.

a) derive a formula for the velocity of the car.
b) how fast is the car moving at 6 hours?
c) derive a formula for the car's acceleration.

My answers:
a)(5)/(1+t)^2
b).102 meters (I KNOW this is wrong!)
c) ????
I just know my answers are wrong if someone could just tell me where I went wrong and how do you solve c).


v=d D/dt= 10 -5/(1+t)^2

acceleration is the first derivative of v, use the v above not yours.

Is b) correct?