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3 years ago

8

An ice skater slides in a straight line across the ice. As she passes a certain point, her velocity is 24 km/hr. Two seconds lat

er it is 13 km/hr. What is the acceleration of the skater?
5.5 km/hr/sec
-5.5 km/hr/sec
11 km/hr/sec
-11 km/hr/sec

1 answer:

gulaghasi [49]3 years ago

5 0

Acceleration = (change in speed) / (time for the change)

Change in speed = (later speed) - (earlier speed) = (13 - 24) = -11 km/hr
Time for the change = 2 seconds

Acceleration = (-11 km/hr) / (2 sec)

Acceleration = -5.5 km/hr-sec (B)

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And if we replace this we got:

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Part b

If we mass is quadrupled we have this:

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The velocity decrease by a factor of 2.

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If the length is quadrupled we have this:

$v_f = \sqrt{\frac{4TL}{m}} = 2} v = 2 *2m/s =4m/s$

The velocity increase by a factor of 2

Part d

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$v_f = \sqrt{\frac{4TL}{4m}} = v = 2m/s$

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