Andy has a remote-controlled car which he uses primarily to annoy the family cat. He has found that the cat’s annoyance is maximized for motion which can be parametrized as x(t) = 0.5t^3 – 3t, where x is in meters and t is in seconds. Calculate the position at t=3.1s in meters. Calculate the acceleration at t=2.3s (m/s2). At what time is the instantaneous velocity zero?

An engineer designs a roller coaster so that a car travels horizontally for 152 ft, then climbs 137 ft at an angle of 34.0° above the horizontal. it then moves 137 ft at an angle of 48.0° below the horizontal. if we take the initial horizontal motion of the car to be along the +x-axis, what is the car's displacement? (give the magnitude of your answer, in ft, to at least four significant figures and give the direction of your answer in degrees counterclockwise from the +x-axis.)

When the force acting on an object points at least partially in the direction of the motion the work done is considered to be negative

Suppose a diode consists of a cylindrical cathode with a radius of 6.200×10^−2 cm , mounted coaxially within a cylindrical anode with a radius of 0.5580 cm . the potential difference between the anode and cathode is 260 v . an electron leaves the surface of the cathode with zero initial speed (v initial=0). find its speed vfinal when it strikes the anode.