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3 years ago

15

You do 30 J of work to load a toy dart gun. However, the dart is 10 cm long and feels a frictional force of 10 N while going thr

ough the dart gunâs barrel. What is the kinetic energy of the fired dart?
a. 30 J
b. 29 J
c. 28 J
d. 27 J

1 answer:

shepuryov [24]3 years ago

6 0

Answer: Option (b) is the correct answer.

Explanation:

The given data is as follows.

$K.E_{1}$ = 30 J, l = 10 cm = 0.1 m (as 1 m = 100 cm)

F = 10 N

The formula to calculate the work done is as follows.

W = $F \times l$

Hence, putting the given values into the above formula as follows.

W = $F \times l$

= $10 N \times 0.1 m$

= 1 J

As the dart loses 1 joule of energy when it goes through the barrel. Therefore, the kinetic energy it has when it comes out is calculated as follows.

K.E = 30 - 1

= 29 J

Thus, we can conclude that the kinetic energy of the fired dart is 29 J.

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