Answer:
0.45 miles
Explanation:
since, car will be running on the edge of track, distance covered in one lap by car will be equal to circumference of track.\
we will use value of pi as 22/7
Circumference for any circular shape is given by 

Hence, in one lap
distance will be covered
in 7 laps
distance will be covered.
but is given that 7 laps should be equal to 10 miles
so 10 miles will be equal to 

Thus, diameter of track will be 0.45 miles to meet the requirement.
<h2>
Answer:When electrons absorb or emit quantized units of energy in the form of photons.</h2>
Explanation:
When a electron is collided with a photon with exactly the same energy it would require to get to any of the farther orbits,electron transition takes place to an orbit depending on the energy of the photon.
When electrons emit exactly the same amount energy that is difference between the current energy level and the new level,then the electron makes a transition to the new level.
Answer:
D
Explanation:
A) is not correct, because the gravitation potential energy will depend on the height the block is located at. It will be calculated with the formula:
U=mgh.
If we take the ground as a zero height reference, then on point 2 the potential energy will be:


While on point 3, the potential energy will be greater.


B) is not the right answer because the kinetic energy will vary with the height the block is located at in the fact that the energy is conserved (this is if we don't take friction into account or air resistance) so in this case:

We already know the potential energy at point 2. We can calculate the kinetic energy at point 3 like this:



So the kinetic energy at point 2 is given by the equation:

so:


As you may see the kinetic energy at point 2 is greater than the kinetic energy at point 3.
C) Is not correct because according to the first law of thermodinamics, energy is not lost, only transformed. So, since we are not taking into account friction or any other kind of loss, then we can say that the amount of mechanical energy at point 1 is exactly the same as the mechanical energy at point 3.
D) Because of what we talked about on part C, this will be the true situation, because the mechanical energy of the block will be the same no matter theh point you measure it at.
Yea but whats the question
Velocity of an object is given as

now we have

time = 3 hours
now from above formula


so its velocity is 40 mph and its a vector quantity whose direction is towards NORTH
correct answer is B