Question 1: On a particular day, the following appliances are used for the times indicated: a 1600-W coffee maker, 12 min, and a 1100-W microwave oven, 4.9 min. With these power requirements, find how much it costs to use these appliances at an electrical cost of 6¢ per kWh. (Do not round your final answer. Fractional cent values are acceptable.)

Question 2: A 0.60-kg block initially at rest on a frictionless, horizontal surface is acted upon by a force of 9.0 N for a distance of 2.0 m. How much farther would the force have to act for the block to have 60 J of kinetic energy?

Question 3: A man pushes a lawn mower on a level lawn with a force of 193 N. If 44% of this force is directed downward, how much work is done by the man in pushing the mower 5.8 m?

Question 4: A 5.0-kg rock is dropped from a height of 12.0 m. At what height is the rock's kinetic energy twice its potential energy?

Question 5: A man pushes a lawn mower on a level lawn with a force of 189 N. If 32% of this force is directed downward, and 74 W of power is expended in pushing the mower 5.8 m, how much time is spent in pushing the mower this distance?

NataleeLeblanc
Feb 26, 2017

#1**+5 **

Question 1:

On a particular day, the following appliances are used for the times indicated: a 1600-W coffee maker, 12 min, and a 1100-W microwave oven, 4.9 min. With these power requirements, find how much it costs to use these appliances at an electrical cost of 6¢ per kWh. (Do not round your final answer. Fractional cent values are acceptable.)

1600W for 12 minutes is

1.6KW for 12/60 hours

which is 1.6*12/60 KW hours = 0.32KW hours

At 6c/KWh that is

0.32*6=$1.92

Now you can work out the microwave oen yourself. :)

Melody
Feb 26, 2017