Answer:
B, C and D are true.
<h3>Explanation:</h3>
A is false because they appear a pale reddish colour not purple.
Answer:
1.35 kJ
Explanation:
KE = ½mv² = ½ × 0.030 kg × (300 m·s⁻¹)² = 1350 J = 1.35 kJ
To solve this task we have to make a proportion, but firstly we have to set up all the main points : so, the distance is s=r(B), that has its <span>r=radius,B=angle in rad
velocity v=ds/dt= w(r)
Do not forget about </span> w = angular speed in rad/s and

Now we can go to proportion




SOLVING FOR A :



or something about <span>10 mph --- SOLVING FOR B.
</span>I'm sure it helps!
Options a to c can be the reasons for scientific models.
But to primarily answer scientific questions,that would require an empirical and experimental approach and not use of models.
Though after getting the answers, models can be built to further explain the answers.
<span>d. answer scientific questions.</span>
Acceleration = (change of speed) / (time for the change)
Change in speed = (22 - 4) = 18 m/s.
Time for the change = 3 sec.
Acceleration = 18/3 = 6 m/s per second.