A runner completes the 200-meter dash with a time of 19.80 seconds. What was the runner's average speed in miles per hour?
1 answer:
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Answer:
The chance in distance is 25 knots
Explanation:
The distance between the two particles is given by:
(1)
Since A is traveling north and B is traveling east we can say that their displacement vector are perpendicular and therefore (1) transformed as:
(2)
Taking the differential with respect to time:
(3)
where and
are the respective given velocities of the boats. To find
and
we make use of the given position for A,
, the Pythagoras theorem and the relation between distance and velocity for a movement with constant velocity.
with this time, we know can now calculate the distance at which B is:
and applying Pythagoras:
Now substituting all the values in (3) and solving for we get:
Answer:
18.4 m
Explanation:
(a)
The known variables in this problem are:
u = 1.40 m/s is the initial vertical velocity (we take downward direction as positive direction)
t = 1.8 s is the duration of the fall
a = g = 9.8 m/s^2 is the acceleration due to gravity
(b)
The vertical distance covered by the life preserver is given by
If we substitute all the values listed in part (a), we find