Physical changes are those which do not affect the chemical properties of a substance. For example, when a paper is cut, the two pieces obtained are still paper. The chemical properties have not changed. Only, physically when one piece is cut to two. A chemical change occurs when the chemical properties change and a new substance with different chemical properties is obtained. For example, when the paper is burnt, it turns to ashes. Hence, this is a chemical change.
When a substance undergoes a physical change, the physical properties of the substance changes like the state (solid to liquid during melting), shape, size, volume etc. Many physical changes are reversible whereas, in general many chemical changes are irreversible.
Answer:
15 m/s
Explanation:
The Speed Of The Car Does Not Add To The Speed Of The Bullet
Your bedroom has a rectangular shape, and you want to measure its area. You use a tape that is precise to 0.001 and find that the shortest wall in the room is 3.547 long. The tape, however, is too short to measure the length of the second wall, so you use a second tape, which is longer but only precise to 0.01 . You measure the second wall to be 4.79 long. Which of the following numbers is the most precise estimate that you can obtain from your measurements for the area of your bedroom?
b)If your bedroom has a circular shape, and its diameter measured 6.32 , which of the following numbers would be the most precise value for its area?
a)30 m^2
b) 31.4 m^2
c)31.37 m^2
d)31.371 m^2
Answer:
Part A

Part B

Explanation:
From the question we are told that
The shortest wall is 
The length of the second wall is 
Generally the area is mathematically evaluated as

=> 
=> 
Given that the diameter is d = 6.32
Then the area is



Answer:
x₁ = 58.09 m
Explanation:
Displacement is calculated by finding the final distance away from a point then subtracting the initial distance.
Given that initial position of object is x=25.89 m
Displacement Δx=32.2 m
Final position x₁=?
Δx = x₁-x
32.2= x₁-25.89
32.2+25.89 = x₁
58.09 m =x₁