Answer:
After 4 s of passing through the intersection, the train travels with 57.6 m/s
Solution:
As per the question:
Suppose the distance to the south of the crossing watching the east bound train be x = 70 m
Also, the east bound travels as a function of time and can be given as:
y(t) = 60t
Now,
To calculate the speed, z(t) of the train as it passes through the intersection:
Since, the road cross at right angles, thus by Pythagoras theorem:
Now, differentiate the above eqn w.r.t 't':
For t = 4 s:
The best scenario to describe the doppler effect would be listening to the siren of a passing ambulance or fire truck
then it is coming towards you, the pitch is higher, it gets higher as it approaches and peaks as it gets right in front of you. then it drop at once when it passes you and continues to drop till it fades away. this is a classic descrption of the doppler effect
200g*1 mole/ 18g=11.1 moles There are 11.1 moles of water.
<span>the speed of something in a given direction. so i think none of these</span>
Explanation:
The acceleration due to gravity g is defined as
and solving for R, we find that
We need the mass M of the planet first and we can do that by noting that the centripetal acceleration 
experienced by the satellite is equal to the gravitational force 
or
The orbital velocity <em>v</em> is the velocity of the satellite around the planet defined as
where <em>r</em><em> </em>is the radius of the satellite's orbit in meters and <em>T</em> is the period or the time it takes for the satellite to circle the planet in seconds. We can then rewrite Eqn(2) as
Solving for <em>M</em>, we get
Putting this expression back into Eqn(1), we get
