Hello,
The answer is to "prove your hypothesis".
Reason:
Researchers do experiments to prove there hypothesis they will most likely do the experiment a few times in older to have the conclusion valid therefore proving his or her experiment.
If you need anymore help feel free to ask me!
Hope this helps!
~Nonportrit
26) A) 400J as GPE = mgh
27) C) Both obj has same PE
28) B) It decreases as energy is not being provided.
29) C) (42 - 0)/7 = 6m/s2
Complete Question
Question 18 (3 points) Solve the problem. (3 points) A solar reflector is made using 31 identical triangular-shaped mirrors, each having sides 2.4m, 2. 3m, 1.5 m. What is the total surface area of the reflector?
A) 33 m2
B) 86 m2
C) 52 m2
D) 34 m2
Answer:
The value is 
Explanation:
From the question we are told that
The sides are a = 2.4 m
b = 2.3 m
c = 1.5 m
Generally the semi perimeter is mathematically represented as
=> 
=> 
Generally the using Heron's formula we have that the surface are a is mathematically represented as
=> 
=>
for acceleration we can define that rate of change in velocity is know as acceleration
So whenever velocity of train is changing with time we can say train is accelerating
Now here if initially train is standstill then after some time its speed is 5 m/s
so here the train is accelerated first time
Then on straight path its speed changed from 5 m/s to 10 m/s so here train gets accelerated second time
After this train chugged around a curve with same speed 10 m/s
SO here since train is moving in curve so here its direction of velocity is continuously changing and this type of acceleration is known as centripetal acceleration
SO this is accelerated Third time
Then its speed decreases and it comes to speed of 5 m/s from 10 m/s
So here it is acceleration of train for Fourth time
Then finally train comes to stop so again its speed changed from 5 m/s to 0
so this is acceleration of train Fifth time
So total train will accelerate 5 times in whole path
