D = distance between the cars at the start of time = 680 km
v₁ = speed of one car
v₂ = speed of other car = v₁ - 10
t = time taken to meet = 4 h
distance traveled by one car in time "t" + distance traveled by other car in time "t" = D
v₁ t + v₂ t = D
(v₁ + v₂) t = D
inserting the values
(v₁ + v₁ - 10) (4) = 680
v₁ = 90 km/h
rate of slower car is given as
v₂ = v₁ - 10
v₂ = 90 - 10 = 80 km/h
Answer: A (
,309.8°)
B (2
, 315°)
C (
, 26.56°)
Explanation: To transform rectangular coordinates into polar coordinates use:
and 
For point A:




°
Point A is in the II quadrant, so we substract the angle for 360° since it is in degrees:

309.8°
Polar coordinates for point A is (
, 309.8°)
For point B:





°
Point B is in IV quadrant, so:

315°
Polar coordinates for point B is (
, 315°)
For point C:





26.56°
Polar coordinates for point C is (
, 26.56°)
I do not know what the school expects as an answer, but advantage of reflecting telescopes is that there is only one major reflecting surface, so it is quite easy to create a 6 or 8 inch telescope by an amateur, after adding on a prism and an eyepiece. (a microscope eyepiece could be used).
MY answer would be "easier to build". (it still takes tens of hours to grind and polish the single plane surface to a parabolic surface).
Electromagnetic waves all have the same velocity in the same medium. However, since frequencies vary widely, so do wavelengths.
Answer: The working and answer can be viewed from the screenshots below. Thanks
Answer:
Part 1) Voltage in secondary windings is 61.08 Volts
Part 2) Current in secondary windings is 0.53 Amperes
Explanation:
The potential developed in the primary and secondary winding of a transformer are related as

where
Np no of turns in primary coil
Ns no of turns in secondary coil
Vp Voltage of turns in primary coil
Vs Voltage of turns in secondary coil
Applying values in the formula we get

Part 2)
Using Ohm's law the current is given by
