Unit: Energy
Year: 1990 Question#: 19
Question: A motor has an output of 1000 watts. When the motor is working at full capacity, how much time will it require to lift a 50-Newton weight 100 meters?
(1 ) 5s
(2 ) 10s
(3 ) 50s
(4 ) 100s
What is this question really asking?
Explanation by: Danny A
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Answer 1
5s
CORRECT
To work this problem out you have to use the work formula. After you find out how much work was done you plug it into the power equation :
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Answer 2
10s
INCORRECT
This is wrong because what you did here was took the power (1000 w) and divided by the distance (100 m) that gives you a meaningless answer.
Try using P=Fs/t return to top
Answer 3
50s
INCORRECT
Try using the formula P=Fs/t return to top
Answer 4
100s
INCORRECT
Try using the formula P=Fs/t return to top
What's this question really asking?
How much time will it take for this 1000 watt machine to lift a 50 N weight to a height of 100 meters high. return to top
