Answer:
A - Sublimation
B - Evaporation
C - Melting
Explanation:
The state of change present in A is Sublimation. Dry Ice is the most common example of Sublimation of everyday life
The state of change present in B is evaporation. Boiling water into water vapor is something that anyone can see.
The state of change present in C is called Melting. Think of Ice melting into a pool of water as the ice heats up.
Answer: D
Explanation: Force can do everything else.
It would take approximately 4.06 hours
Answer:
Option C, The total momentum of the fragments is equal to the original momentum of the firecracker.
Explanation:
Kinetic energy of cracker cannot remain constant before and after explosion. It is so because in the process of burning and bursting some amount of kinetic energy is lost in the form of light and heat energy. While the total mass before and after the explosion remains constant due to which the momentum is conserved before and after the explosion
Hence, option C is correct
Answer:
The man moves across the ice with a speed of 0.345m/s.
Explanation:
From the conservation of linear momentum, we have that the total linear momentum before the book throw is equal to the total linear momentum just after it. Since the initial velocity of the system is zero (so the initial momentum is zero), we have that:
Where 
is the mass of the man, 
is the mass of the book, and 
and 
are their velocities. Plugging in the given values, we can compute the speed of the man (ignoring the negative sign, because we care about the magnitude, not the direction):
In words, the resulting speed of the man is 0.345m/s.
