(a) The skater covers a distance of S=50 m in a time of t=12.1 s, so its average speed is the ratio between the distance covered and the time taken:

(b) The initial speed of the skater is

while the final speed is

and the time taken to accelerate to this velocity is t=2 s, so the acceleration of the skater is given by

(c) The initial speed of the skater is

while the final speed is

since she comes to a stop. The distance covered is S=8 m, so we can use the following relationship to find the acceleration of the skater:

from which we find

where the negative sign means it is a deceleration.
When a liquid is cooled, the kinetic energy of the particles, DECREASES..
The velocity of the boat after the package is thrown is 0.36 m/s.
<h3>
Final velocity of the boat</h3>
Apply the principle of conservation of linear momentum;
Pi = Pf
where;
- Pi is initial momentum
- Pf is final momentum
v(74 + 135) = 15 x 5
v(209) = 75
v = 75/209
v = 0.36 m/s
Thus, the velocity of the boat after the package is thrown is 0.36 m/s.
Learn more about velocity here: brainly.com/question/6504879
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CHECK COMPLETE QUESTION BELOW
you stood on a planet having a mass four times that of earth mass and a radius two times of earth radius , you would weigh?
A) four times more than you do on Earth.
B) two times less than you do on Earth.
C) the same as you do on Earth
D) two times more than you do on Earth
Answer:
OPTION C is correct
The same as you do on Earth
Explanation :
According to law of gravitation :
F=GMm/R^2......(a)
F= mg.....(b)
M= mass of earth
m = mass of the person
R = radius of the earth
From law of motion
Put equation b into equation a
mg=GMm/R^2
g=GMm/R^2
g=GM/R^2
We know from question a planet having a mass four times that of earth mass and a radius two times of earth radius if we substitute we have
m= 4M
r=(2R)^2=4R^2
g= G4M/4R^2
Then, 4in the denominator will cancel out the numerator we have
g= GM/R^2
Therefore, g remain the same