While goofing off at the ice skating rink, a student takes off her shoes and places each of them on the ice. Her friend, a hocke
1 answer:
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Given:
Total distance = 1000 kilometer
Total time = 5 hours
To find:
Average speed = ?
Formula used:
=
Where = average speed
s = total distance
t = total time
Solution:
Average speed of the jet is given by,
=
Where = average speed
s = total distance
t = total time
=
= 200 km/ h
Thus, average speed of the jet is 200 km/h.
Hence, Option (A) is correct.
There are some missing data in the text of the problem. I've found them online:
a) coefficient of friction dry steel piston - steel cilinder: 0.3
b) coefficient of friction with oil in between the surfaces: 0.03
Solution:
a) The force F applied by the person (300 N) must be at least equal to the frictional force, given by:
where
is the coefficient of friction, while N is the normal force. So we have:
since we know that F=300 N and
, we can find N, the magnitude of the normal force:
b) The problem is identical to that of the first part; however, this time the coefficienct of friction is
due to the presence of the oil. Therefore, we have:
a) coefficient of friction dry steel piston - steel cilinder: 0.3
b) coefficient of friction with oil in between the surfaces: 0.03
Solution:
a) The force F applied by the person (300 N) must be at least equal to the frictional force, given by:
where
since we know that F=300 N and
b) The problem is identical to that of the first part; however, this time the coefficienct of friction is