I don't think that 4m has anything to do with the problem.
anyway. here.
A___________________B_______C
where A is the point that the train was released.
B is where the wheel started to stick
C is where it stopped
From A to B, v=2.5m/s, it takes 2s to go A to B so t=2
AB= v*t = 2.5 * 2 = 5m
The train comes to a stop 7.7 m from the point at which it was released so AC=7.7m
then BC= AC-AB = 7.7-5 = 2.7m
now consider BC
v^2=u^2+2as
where u is initial speed, in this case is 2.5m/s
v is final speed, train stop at C so final speed=0, so v=0
a is acceleration
s is displacement, which is BC=2.7m
substitute all the number into equation, we have
0^2 = 2.5^2 + 2*a*2.7
0 = 6.25 + 5.4a
a = -6.25/5.4 = -1.157
so acceleration is -1.157m/(s^2)
Answer:
Electromagnetic field, a property of space caused by the motion of an electric charge. A stationary charge will produce only an electric field in the surrounding space. If the charge is moving, a magnetic field is also produced. An electric field can be produced also by a changing magnetic field.
Answer:
The amount of time for the whole journey is 8 hours.
Explanation:
A truck covered 2/7 of a journey at an average speed of 40 mph. Representing 1 the total of the trip traveled, then the rest of the distance traveled is calculated as: 
So if the truck covered the remaining 200 miles at
, this means that
of the trip represents the 200 miles. So, to calculate the total distance traveled by the truck, you apply the following rule of three: if
of the route represents 200 miles, the integer 1 (which represents the total of the route), how many miles are they?

miles= 280
So the total distance traveled is 280 miles. Since speed is the relationship between the space traveled by an object and the time used for it (
), then if the average of the entire trip was 35 mph and the distance traveled 280 miles, the time is calculated as:

time= 8 h
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The amount of time for the whole journey is 8 hours.</em></u>
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Answer:
you will get huge electricity bills ............
Answer:

Explanation:
We can use Newton's Universal Law of Gravitation to solve this problem:
., where
is acceleration due to gravity at the planet's surface,
is gravitational constant
,
is the mass of the planet, and
is the radius of the planet.
Since acceleration due to gravity is given as
, our radius should be meters. Therefore, convert
kilometers to meters:
.
Now plugging in our values, we get:
,
Solving for
:
.