Given:
Mass of the rail road car, m = 2 kg
velocity of the three cars coupled system, v' = 1.20 m/s
velocity of first car,
= 3 m/s
Solution:
a) Momentum of a body of mass 'm' and velocity 'v' is given by:
p = mv
Now for the coupled system according to law of conservation of momentum, total momentum of a system before and after collision remain conserved:
(1)
where,
= velocity of the first car
= velocity of the 2 coupled cars after collision
Now, from eqn (1)


v' = 1.80 m/s
Therefore, the velocity of the combined car system after collision is 1.80 m/s
Bob's average speed was 80 m/s.
His average velocity was 40 m/s East.
The magnitude of his velocity was almost 4 times as fast as Usain Bolt's world record in the 100 meters, or about 89 mph. His speed was double that.
Answer:
Because concave mirror focus the sunlight at one particular point . At that particular point , amount of sunlight is converged and heat is trapped at that point . This is because , it burn the paper on which the image is focussed .
Answer:
* If it is an incandescent lamp, the increase in temperature of the towel could set it on fire,
* If the towel is wet, there could be a short circuit
Explanation:
Covering the lamp with a towel has several problems:
* If it is an incandescent lamp, the increase in temperature of the towel could set it on fire, which could be a danger
* If the lamp is not incandescent, the temperature rise of the towel is not very high,
* If the towel is wet, there could be a short circuit due to the humidity of the lamp with the wet towel
* If the towel is wet when touched, there could be a shock towards the person due to the electrical conduction
Consequently, covering the bulb with a towel is a serious mistake.
Hi
There is a basic difference<span>, because </span>mass<span> is the actual amount of material contained in a body and is measured in kg, gm, etc. Whereas </span>weight<span> is the force exerted by the gravity on that object mg. Note that </span>mass<span> is independent of everything but </span>weight<span> is different on the earth, moon, etc.</span>