Answer:
Reflective clothing. So vehicles can see them and stuff.
Answer:
the wavelength is 9.8 meters
Explanation:
We can use the relationship:
Velocity = wavelenght*frequency.
Initially we have:
wavelenght = 4.9m
velocity = 9.8m/s
then:
9.8m/s = 4.9m*f
f = 9.8m/s/4.9m = 2*1/s
now, if the velocity is doubled and the frequency remains the same, we have:
2*9.8m/s = wavelenght*2*1/s
wavelenght = (2*9.8m/s)*(1/2)s = 9.8 m
law of conservation of energy
aka the first law of thermodynamics
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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