Which of these are characteristics of good experimental design? Check all that apply.

-Good experimental design uses different methods for trials in an experiment.
-Good experimental design allows scientists to replicate experiments.
-Good experimental design tests only one variable at a time.
-Good experimental design plans how to record data so the data can be published.
-Good experimental design involves only one trial in an experiment.
-Good experimental design includes logging every step and data point of the experiment.

The correct answer is

-Good experimental design allows scientists to replicate experiments

-Good experimental design tests only one variable at a time

-Good experimental design plans how to record data so the data can be published

-Good experimental design includes logging every step and data point of the experiment

(newtons first law)

conservation of momentum law states :

momentum before collision = momentum after collision

momentum p (kg-m/s)= mass * velocity

say moving car=1 000 kg, velocity = 10 m/s then p = 1 000*10= 10 000 kg-m/s

say still car = 2 000 kg, velocity = 0 m/s then p = 2 000* 0 = 0 kg-m/s

total momentum prior to collision = 10 000 + 0 = 10 000 kg-m/s

momentum after collision = 10 000 kg-m/s

mass now = 1 000 kg+2 000 kg = 3 000 kg

10 000 = 3 000 kg* velocity m/s

10 000/3 000 = velocity

3.33 m/s = velocity after collision

an impulse is a force applied over time , momentum is exclusive of external forces and a perfect collision is implied

yes the answer is total mass in unchanged   : )