The best answer to this question is D. a god scientific question should be based on observations instead of just imagination.
Hope this helps.
Answer:
B. An Iron Bar place in a room becomes cooler than its surroundings.
-- Take a straight ruler.
-- Lay it down with the 'zero' mark at the start point.
-- Rotate it around the start point until the end point is also touching the edge of the ruler.
-- From the marks on the ruler, read the straight-line distance from the start point to the end point.
-- Without moving the ruler, observe and write down the DIRECTION from the start point to the end point.
-- The Displacement is the straight-line distance and direction from the start point to the end point.
Answer:
The statements A and D are true
The statements B and C are false
Explanation:
The force between charges can be explained by the Coulomb's Law.
According to Coulomb:
1 - Like charges always repel each other
2- Unlike or opposite charges always attrack each other
3- Force between 2 charges is given by:

where F is the force between 2 charges and r is the distance between 2 charges.
We can see that Force F is inversely proportional to the distance r
Which means that when F increase, r decreases and when F decreases, r increases
Answer:
The error in tapping is ±0.02828 ft.
Explanation:
Given that,
Distance = 200 ft
Standard deviation = ±0.04 ft
Length = 100 ft
We need to calculate the number of observation
Using formula of number of observation

Put the value into the formula


We need to calculate the error in tapping
Using formula of error


Put the value into the formula


Hence, The error in tapping is ±0.02828 ft.