Answer:
For the first one, its B) cities B and C
I'm not so sure, but I hope this helps.
The average velocity of the car for the whole journey is 69.57 km/h.
The given parameters:
- <em>Length of the road, L = 320 km</em>
- <em>Distance covered = 240 km at 75 km/h</em>
- <em>time spent refueling, t₂ = 0.6 hr</em>
- <em>Final velocity, = 100 km/hr</em>
The time spent by the before refueling is calculated as follows;

The time spent by the car for the remaining journey;

The total time of the journey is calculated as follows;

The average velocity of the car for the whole journey is calculated as follows;

Learn more about average velocity here: brainly.com/question/6504879
Answer:
Explanation:distance-time =speed
a,V =s/t
V=2m/2s
V=1m/s
b,v=s/t
V=80m/40s
V= 2m/s
The average speed is 2m/s
Answer:
Explanation: This is done using the equation:

Because the Radius is a know value. We have the following.

Which is:
4188.7902 mm
Answer:
Explanation:
Diffraction grating is used to form interference pattern of dark and bright band.
Distance between adjacent slits (a ) = 1 / 420 mm
= 2.38 x 10⁻³ mm
2.38 x 10⁻⁶ m
wave length of red light
= 680 x 10⁻⁹ m
For bright red band
position x on the screen
= n λD / a , n = 0,1,2,3 etc
D = distance of screen
putting n = 1 , 2 and 3 , we can get three locations of bright red band.
x₁ = λD / a
= 680 x 10⁻⁹ x 2.8 / 2.38 x 10⁻⁶
= .8 m
= 80 cm
Position of second bright band
= 2 λD / a
= 2 x 80
= 160 cm
Position of third bright band
= 3 λD / a
= 3 x 80
= 240 cm