A student lifts a backpack straight up from the ground to 1.2 m with a force of 45.5 N. How much work is done to the backpack. please help! C:

What is the most useful equation for electric power?

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.

You are your friend move a new refrigerator into his kitchen. you apply a horizontal force of 252 n in the negative x direction to try and move the 56 kg refrigerator. the coefficient of static friction is 0.61. (a) how much static frictional force does the floor exert on the refrigerator? give both magnitude (in n) and direction. magnitude n direction (b) what maximum force (in n) do you need to apply before the refrigerator starts to move?