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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The marbles that are 'more energetic' fall out of the tray, in the same way particles have enough energy to escape and turn into a gas.
Answer: The sound will change due to changes in frequency and the wavelength of the airplane.
Explanation: Let assume that the observer is at a stationary position. The wavelength of the sound from the airplane reduces and the frequency increases as the plane is moving toward the observer. As the airplane passes by, that is, moving away from the observer, the frequency starts to reduce while the wavelength of the sound starts to increase.
The sound that the observer hears will change base on the illustration above.
Gravity decreases your kinetic energy when you are driving uphill since the direction of motion is opposite for both. Driving uphill is force going upward while gravity pulls object down. When it is going downhill, the car tends to go faster since the gravity helps the object to go down by adding another value to the total acceleration of the motion of the object. Using the forces of balance, an object going up tends to become heavier while object going down tends to become lighter because of the gravity factor. Another analogy is the motion of elevators going up and down that incurs effects to your weiight.
