25,000 Feet = 7620m
PE = mgh where m is mass, g is gravity accel: 9.8 n h is height
= 90 x 9.8 x 7620
= 6720840J
= 6.72MJ
F = ma where m is mass, a is accel = gravity = 9.8
= 90 x 9.8
= 882N
Accel = gravity = 9.8m/s^2
KE = 1/2mv^2 where m is mass n v is vel
if no wind resistance, PE leaving airplane = KE at net
6720840 = 1/2 x 90 x v^2
v^2 = 149352
v = 386.5m/s
Julia walks from the park, which is six blocks east of her house, to the store, which is three blocks east of her house. Julia walks for 5 minutes. This walk's average speed will be 1.2 blocks per minute. Option B is correct.
<h3>What is displacement?</h3>
Displacement is defined as the shortest distance between the two points. Distance is the horizontal length covered by the body. While displacement is the shortest distance between the two points.
Displacement is a vector quantity .its unit is m.
The average velocity on this walk will be;

Hence option B is correct.
To learn more about displacement refer to the link; brainly.com/question/10919017
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Answer:
Part a)

Part b)

Explanation:
As per momentum conservation we know that there is no external force on this system so initial and final momentum must be same
So we will have




Part b)
By equation of kinetic energy we have




2m/s
Explanation:
Given parameters:
Distance traveled = 60m
time taken = 30seconds
Unknown:
Speed of skateboarder = ?
Solution:
Speed is the rate of change of distance with time taken. It is a scalar quantity that only revers magnitude;
Speed = 
Speed =
= 2m/s
learn more:
Speed brainly.com/question/1548911
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