Ok, let me see if I can help
Sound is caused by vibrations. These can pass through a solid, liquid, and gas. But not through vacuum because there are no particles
The resistance of a wire is directly proportional to the length of the wire. That is the longer the length of the wire, the higher the resistance and the shorter the length of the wire, the smaller the resistance.
There are two ways to solve this. The longer way is to use those equations to calculate numbers for total distance.
The easier way is to find the area under the graph. That's right, AREA UNDER VELOCITY-TIME graph is the TOTAL DISTANCE travelled!
it's a shortcut.
Let's split up the area into a triangle and rectangle:
Triangle = 0.5(4-0)(10-0) = 20 m
Rectangle = (6-4)(10-0) = 20 m
Total distance = 40 m!
its B 0.225kPa using the formula p=f/A then change the pascals into kpa
Explanation:
We have,
Surface area, 
The current varies wrt time t as :
(a) At t = 2 seconds, electrical charge is given by :
(b) Current is given by :
Instantaneous current at t = 1 s is,
(c) Current is, 
Current density is given by electric current per unit area.
Therefore, it is the required explanation.
