Answer:

Explanation:
Ok, the average speed can be calculate with the next equation:
(1)
Basically the car cover the same distance "d" two times, but at different speeds, so:

and the total time would be the time t1 required to go from A to B plus the time t2 required to go back from B to A:

From basic physics we know:

so:


Using the previous information in equation (1)

Factoring:
(2)
Finally, replacing the data in (2)

Answer:D
Explanation:
It was right o khan academy
Answer:
1,373.4 N
Explanation:
The mass of the table acts at the centre in addition to the books since that is the centre of gravity of the table.
Mass of books will be 10kg+20kg+30kg=60 kg
Total mass of table and books will be 500kg+60kg=560 kg
This mass is evenly distributed into the four legs hence 560kg/4 legs=140 kg per leg
Force is product of mass and acceleration due to gravity hence F=gm
Taking g as 9.81 m/s2 then
F=140*9.81=1,373.4 N
Therefore, rhe normal force is equivalent to 1,373.4 N
Answer:
v = 895 m/s
Explanation:
Time period is given as 39 Earth Days


now the radius of the orbit is given as

so the total path length is given as



now the speed will be given as



Answer:
a)θ=71.89°
b)NO
Explanation:
Given that
For glass n= 1.38
We know that for air n'=1
The angle for total internal reflection θc given as
sin θc=n'/n
By putting the values
sin θc=n'/n
sin θc=1/1.38
θc=46.43°
n'sinθ = n sinθref
sinθref = cosθc
n'sinθ = n cosθc
1 x sinθ =1.38 x cos 46.43°
θ=71.89°
b)
NO