Answer:
1- For the track B. The potential energy is the same for the two cars, but because of the slope of the track, the car B earn kinetic energy faster. The gravitation acceleration of the cars will be g•sinθ, and the angle of the track B will have a bigger value for sinθ
2- The conservation of energy applies because the roller coaster is a closed track. When a car climb the track, it earn GPE, which is given by mgh, when it get down in the track, it transform GPE in KE, which is given in 1/2mv².
3-
Position of car (m) GPE KE GPE + KE
top (30m) 60000 0 60000
bottom (0m) 0 60000 60000
halfway down (15m) 30000 30000 60000
three-quarters way down 15000 45000 60000
Answer:
27.5 days
0.92 month
Explanation:
= radius of the orbit of moon around the earth = 
= Mass of earth = 
= Time period of moon's motion
According to Kepler's third law, Time period is related to radius of orbit as

inserting the values, we get

we know that
1 day = 24 hours = 24 x 3600 sec = 86400 s

1 month = 30 days

Answer:
The speed of the 1 kg red ball 8.04 m/s .
Explanation:
Given :
Separation between rods , d = 1.5 m .
Mass of the red ball is 1 kg .
Mass of the orange ball is 5.7 kg .
Angular velocity ,
.
Now , distance of center of mass from red ball is :

We know , speed is given by :

Hence , this is the required solution .
Let A = i+j+k be a vector and B = 3 be any scalar,
Multiplying A and B,
AB = (i+j+k)3 = 3i+3j+3k
Which is a new vector whose direction is same as the old but it's 3 times greater in length than the old vector(i+j+k).
Now, dividing A and B,
A/B = (i+j+k)/3 =

Which is again a new vector whose direction is same as the old but now it's 1/3 times small in length than the old vector.
Direction is same because we multiplied by positive scalar. If we multiply A by suppose -1, -4, -1000000 or any negative number, it's direction will reverse.
Thus, if we multiply a vector with scalar, it's length increases. If we divide, it shrinks.