# L.J

Popular questions and responses by L.J-
## calculus

the displacement (in meter) of a particle moving in a straight line is given by the equation of motion s=5t^3+4t+2, where t is measured in seconds. Find the velocity of the particle at t=3.

*asked on November 17, 2011* -
## calculus

A man starts walking north at 3ft/s from a point P. Five minutes later, a woman starts walking south at 6ft/s from a point 500ft due east of P. At what rate are the people moving apart 15min after the woman starts walking?

*asked on November 17, 2011* -
## calculus

Two cars start moving from the same point. One travels south at 28mi/h and the other travels west at 50mi/h. At what rate is the distance between the cars increasing 4 hours later?

*asked on November 17, 2011* -
## calculus

if a snowball melts so that its surface area decreases at a rate of 1 cm^2/min, find the rate at which the diameter decreases when the diameter is 43cm. Leave pi in your answer please.

*asked on November 17, 2011* -
## calculus

a plane flying horizontally at an altitude of 2 mi and a speed of 460 mi/h passes directly over a radar station. find the rate at which the distance from the plane to the station is increasing when it is 5 mi away from the station.

*asked on November 17, 2011* -
## calculus

the cost (in dollars) of producing x units of a certain commodity is C(x)=5090+13x+0.09x^2. Find the average rate of change with respect to x when the production level is changed from x=105 to x=107.

*asked on November 17, 2011* -
## calculus

Find a, such that the function f(x)=3x+rad(a-x^2) has the domain [-6,6].

*asked on November 17, 2011*