Answer:
A physical change
Explanation:
You are wiping chalk particles from the board to the eraser which is just changing the location of the chalk particles, a physical change.
you're not changing the chalk into a new substance or causing a chemical reaction, which would be a chemical change.
Answer:
d = 2 [m].
Explanation:
To solve this problem we must use the principle of conservation of energy, where the mechanical energy in a state plus the work done on the body, must be equal to the mechanical energy in the state E. This can be easily represented in the following equation.

where:
Ea = Mechanical energy in A [J]
Wa-e = Work among states a and e [J]
Ee = Mechanical energy in E [J].
The key to being able to understand this problem is that in state A, we only have kinetic energy, while the energy in state E is equal to zero (there is no movement). The work is equal to the product of force by distance, as work acts in the opposite direction to movement, this has a negative sign.
![10 - F*d = 0\\5*d = 10\\d = 10/5\\d = 2 [m]](https://tex.z-dn.net/?f=10%20-%20F%2Ad%20%3D%200%5C%5C5%2Ad%20%3D%2010%5C%5Cd%20%3D%2010%2F5%5C%5Cd%20%3D%202%20%5Bm%5D)
Answer:
2500N
Explanation:
f = m.a
m=500 kg
a=5 m/s²
f = 5*500 kgm/s² = 2500 N
There is a basic difference, because mass is the actual amount of material contained in a body and is measuredin kg, gm, etc. Whereas weight is the force exerted by the gravity on that object mg. Note that mass is independent of everything but weight is different on the earth