Answer:
68.57 mile/hour
Explanation:
The distance from Yakima to Ellensburg is 50 miles and you travel with 60 miles/hour for the first 25 miles, then 80 miles/hour for the last 25 miles. The easy way to solve this question is to find the total time needed to travel.
The time needed to travel 25 miles with 60 miles/hour speed will be: 25 miles/ (60 miles/hr)= 0.42 hr
The time needed to travel 25 miles with 80 miles/hour speed will be: 25 miles/ (80 miles/hr)= 0.31 hr
Total time needed to travel 50 miles will be: 0.41 hr + 0.31hr = 0.73 hr
The average speed will be:
average speed= sum of travel distance/ sum of time needed= 50 miles/ 0.73hr= 68.57 mile/hr
Because the strength of the gravitational forces between two objects
depends on the distance between the objects' centers, and when your
elevation changes, so does the distance between your center and the
center of the Earth.
Answer:
(a)
(b)
(c)
Explanation:
The Planck-Einstein relation allows us to know the energy (E) of a photon, knowing its frequency (f). According to this relation, the energy of the photon is defined as:
Here h is the Planck constant.
(a)
(b)
(c)
Answer:
Georges Lemaître - theorized that the universe had a beginning
Albert Einstein - huit a model of the inverse haced on relativity
Galileo Galilei - was the first to use a telescope to observe the planets
Edwin Hubble - showed that the universe was expanding
Henrietta Swan Leavitt - demonstrated a method to calculate the distance of celestial bodies
is my choices report if wrong
Answer: 208.3 s
Explanation:
Hi!
You need to calculate the velocity of the boat relative to the shore, in each trip.
Relative velocities are transformed according to:
Let's take the upstram direction as positive. Water flows downstream, so it's velocity relative to shore is negative , -2 m/s
In the upstream trip, velocity of boat relative to water is positive: 10m/s. But in the downstream trip it is negatoive: -10m/s
In upstream trip we have:
In dowstream we have:
In both cases the distance travelled is 1000m. Then the time it takes the round trip is: