Answer:
The law of conservation of mass or principle of mass conservation
Explanation:
It states that for any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as the system's mass cannot change, so quantity can neither be added nor be removed.
Answer:
D. The period would decrease by sqrt (2)
Explanation:
The period of a mass-spring system is given by:

where
m is the mass
k is the spring constant of the spring
If the spring constant is doubled,
k' = 2k
So the new period will be

So the correct answer is
D. The period would decrease by sqrt (2)
Answer:
6 N
Explanation:
= Mass flow rate = 1 kg/s
v = Final velocity = 6 m/s
u = Initial velocity = 0 m/s
Force is obtained when we divide change in momentum by time

The force the person exert on the extinguisher in order to prevent it from accelerating is 6 N
This means acceleration a is constant.
Let
a) vo be the initial speed, at t=0
b) v be the final speed after time t
c) d distance travelled in time t
Then we have:
a) v=vo+a×t
b) v²=vo²+2×a×d (Galilei's equation)
c) d=vo×t+a×t²/2
d) average speed vm=(vo+v)/2
Acceleration due to gravity will be constant, but the speed can change.