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natima [27]
3 years ago
9

A weightlifter expends 294 w of power lifting a weight to a height of 2 m in 10 seconds. what mass has he lifted?

Physics
1 answer:
Masja [62]3 years ago
3 0
The power of the weightlifter is equal to the ratio between the work done by it and the time taken:
P= \frac{W}{t}
since we know the power and the time, we can find the work done:
W=Pt=(294 W)(10 s)=2940 J

For the work-energy theorem, this work done by the lifter is equal to the gravitational potential energy gained by the mass, which is given by:
U=mg \Delta h
where m is the mass and \Delta h is the increase in height. Rearranging the formula and using W=U, we can find the mass:
m= \frac{U}{g\Delta h}= \frac{2940 J}{(9.81 m/s^2)(2 m)}=149.8 kg
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A)

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C)

The train does not stop at the stoplight. How far behind the train is the car when the car reaches its original speed v0 again? Express the separation distance in terms of v0 and a0 . Your answer should be positive.

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