Answer:
Ek1 = 900000 [J]
Ek1 = 400000 [J]
Explanation:
In order to solve this problem we must remember that kinetic energy is defined as the product of mass by velocity squared by a medium. Therefore using the following equation we have:

where:
m = mass = 500 [kg]
v1 = 60 [m/s]
So we have:
Ek1 = 0.5*500*(60^2)
Ek1 = 900000 [J]
and:
Ek2 = 0.5*500*(40^2)
Ek2 = 400000 [J]
The answer is option D)
this is because the heat radiated by the flame is mostly absorbed by the air surrounding it, so the air becomes hot and its density decreases (because of expansion), therefore it goes up and it is replaced by cooler air. since all of the hot air flies up, non goes side ways to heat up the match stick, hence it remains cool and does not light up.
option A) also sounds correct, but it isn't. this is because the flame IS hot enough to burn the match stick, it's just that the match stick is positioned the wrong way
Solution :
Given :
M = 0.35 kg

Total mechanical energy = constant
or 
But
and 
Therefore, potential energy at the top = kinetic energy at the bottom


(h = 35 cm = 0.35 m)
= 2.62 m/s
It is the velocity of M just before collision of 'm' at the bottom.
We know that in elastic collision velocity after collision is given by :

here, 
∴ 

= 0.33 m/s
Therefore, velocity after the collision of mass M = 0.33 m/s