2. A car of mass 1.1 x 10kg negotiates a level curve at a constant speed of 22 m/s. The
curve has a radius of 85 m.
(a) Draw an FBD of the car and name the force
that provides the centripetal acceleration.
(b) Determine the magnitude of the force named
in part (a) that must be exerted to keep the car
from skidding sideways.
(c) Determine the minimum coefficient of static
friction needed to keep the car on the road.

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".