+0

+5
356
4
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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?

physics
NataleeLeblanc  Feb 26, 2017

#2
+5

A little boo-boo.  0.32*0.06 =\$0.0192 or 1.92cents

Guest Feb 26, 2017
#1
+92805
+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
#2
+5

A little boo-boo.  0.32*0.06 =\$0.0192 or 1.92cents

Guest Feb 26, 2017
#3
+92805
0

Thanks.

My boo was a little different.  I did intend  0.32*6 and i knew the anwer was cents but then i wrote it wrong.

I am pleased that you picked the error up :)

Melody  Feb 26, 2017
#4
+26753
+5

Answers to questions 2 to 5:

.

Alan  Feb 27, 2017