Let the mass of 2500 kg car be
and it's velocity be
and the mass of 1500 kg car be
and it's velocity be
.
After the bumping the mass be M and it's velocity be V.
By law of conservation of momentum we have

2500 * 5 + 1500 * 1=4000 * V
V = 14000/4000 = 7/2 = 3.5 m/s
So the velocity of the two-car train = 3.5 m/s
Answer:
6.1328 kg
60.16284 N
Explanation:
r = Radius of ball = 0.11 m
= Density of fluid =
(Assumed)
g = Acceleration due to gravity = 9.81 m/s²
m = Mass of ball
V = Volume of ball = 
The weight of the bowling ball will balance the buouyant force

The mass of the bowling ball will be 6.1328 kg
Weight will be 
Answer:
The impression of the image on the retina lasts for about 1/16th of a second after the removal of the object. If a burning stick of incense is revolved at a rate of more than sixteen revolutions per second, we see a circle of red light due to persistence of vision.
Explanation: