Me with these questions as soon as possible i need to turn it
a 60 watt light bulb uses 60 joules of electrical energy every second. however, only 6 joules of electrical energy is converted into light energy each second.
a. what is the efficiency of the light bulb? give your answer as a percentage.
b. what do you think happens to the “lost” energy?
19. the work output is 300 joules for a machine that is 50% efficient. what is the work input?
20. a machine is 75% efficient. if 200 joules of work are put into the machine, how much work output does it produce?

When an object moves in uniform circular motion, the direction of its acceleration is a) in the same direction as its velocity vector. b) in the opposite direction of its velocity vector c) is directed toward the center of its circular path. d) is directed away from the center of its circular path. e) depends on the speed of the object.

Aperson gives a shopping cart an initial push along a horizontal floor to get it moving, and then lets go. the cart travels forward along the floor, gradually slowing as it moves. consider the horizontal force(s) on the cart while it is moving forward and slowing. which of the following statements is correct? (a) both a forward and a backward force are acting on the cart, but the forward force is larger. (b) only a forward force is acting which diminishes with time. (c) both a forward and a backward force are acting on the cart, but the backward force is larger. (d) only a backward force is acting, no forward force.

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.