Missing question (found on internet):
"what is the force of the car?"
Solution:
According to Newton's second law, the force of the car is equal to the product between its mass and its acceleration:

For the car in the problem,


So the force that accelerates the car is
Answer:
<h3>
The coefficient of kinetic friction between the puck and the ice is
0.12</h3>
Explanation:
Given :
Initial speed 
Displacement
m
From the kinematics equation,

Where
final velocity, in our example it is zero (
),
acceleration.


From the formula of friction,

Minus sign represent friction is oppose the motion
Where
( normal reaction force )
( ∵
)
So coefficient of friction,


Therefore, the coefficient of kinetic friction between the puck and the ice is
0.12 .
Given data:
Yan speed;

Christopher speed;

Christophe starts 30 s later than Yan. Therefore, Christophe takes 30 s less than Yan to reach the same distance.
Part (A)
The distance is given as,

Let both Yan and Christophe meet at d distance from the start position. Therefore,

Substituting all known values,

Therefore, 600 s after Yan's departure Christophe will join him.
Part (B)
The distance is given as,

Substituting all known values,

Therefore, Christophe joins Yan after 6.17 km from the start.
Because the atsmosphere in the sky makes it less gravity so air craft needs these cabins