When a large rock is weathered into tiny pieces which add up the weight of the original rock, this demonstrates the law of conservation of matter.
According to this law the mass of an object doesn't change with time and also it does not depends on how the particles are arranged themselves.
Hence, option (C) is correct.
Answer:
( 1000 × 4 = 4,000) (800×3= 2400) (800×2=1600) the answer is 1600 hope it helps
#2
As it is given here
initial speed is

After 4 seconds the final speed is

so here we can use the formula of acceleration using kinematics



so here it will accelerate at 2 m/s^2 rate.
#3
As it is given here
initial it starts from rest

After 2.5 seconds the final speed is

so here we can use the formula of acceleration using kinematics



so here it will accelerate at 6 m/s^2 rate.
#4
i think question is not correct as in first line it is saying about a bag of trash and then in next line it is asking for the position of Jumper and bridge.
Not sure but i will say D
Here is the answer to your question