A 30 kg box is pushed along a horizontal surface. The person pushing the box pushes with a constant force of 300 N directed at an angle of 30° below the horizontal. If the box starts from rest and reaches a speed of 5 m/s after only 2 seconds of pushing, find the force of friction acting on the box.

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.