Kinematics of particles

The position of a particle that traverses a straight line is expressed as $$x(t)=t^3+2t^2-t+10$$, where x is in feet and t in seconds. What is the acceleration (ft/$$sec^2$$) of the particle when the velocity is zero?

The distance of a particle traveling on a straight line from point A is $$s=10t^2+t^3$$. The rate of change of acceleration at time $$t=4$$ is:

A tractor with a mass of 2,300 kg is traveling at 10 m/s. At time t = 0, the driver pulls the emergency brake and the tractor begins to slide. The properties of the relevant materials, are shown:

At t = 3, the speed (m/s) of the tractor is most nearly:

A 10-kg block which starts at rest, begins sliding after being pushed by a constant force F of 15N.  The time in seconds it takes for the block to reach 20 m/s is most nearly.

A sea vessel accelerates at a rate of $$22\ ft//sec^2$$. The vessel travels 140 ft while its speed changes to 70 ft/sec. The initial velocity (ft/sec) was most nearly: