The unit of electric current is the Ampere.
1 Ampere of current means that if you set up your chair and
stare at the electrons flowing past one point in the circuit, you'll
see 1 coulomb of charge passing that point every second.
How will you recognize 1 coulomb of charge ?
Well, every electron carries the same amount of charge, and
we know how much that is. (Read about the Millikan oil-drop
experiment in 1909.) So we know how many electrons it takes
to carry 1 coulomb of charge past the point you're watching.
All you have to do is count the electrons as they zip past.
Every time you count 6,241,509,343,000,000,000 electrons,
you can tick off 1 coulomb of total charge that they're carrying.
If you reach that count every second, you know the current
passing that point is 1 Ampere.
Answer:
A) It takes the truck 8 s to catch the motorcycle.
B) The motorcycle has traveled 160 m in that time.
C) The velocity of the truck is 40 m/s at that time.
Explanation:
The equations of the position and velocity of an object moving in a straight line are as follows:
x = x0 +v0 · t + 1/2 · a · t²
v = v0 + a · t
Where:
x = position
x0 = initial position
v0 = initial velocity
t = time
a = acceleration
v = velocity at time t
(A) When the the truck catches the motorcycle, both have the same position. Notice that the motorcycle moves at constant speed so that a = 0:
x truck = x motorcycle
x0 +v0 · t + 1/2 · a · t² = x0 + v · t
Placing the origin of the frame of reference at the point where the truck starts, both have an initial position of 0. The initial velocity of the truck is 0. Then:
1/2 · a · t² = v · t
solving for t:
t = 2 v/a
t = 2 · 20 m/s/ 5 m/s²
t = 8 s
It takes the truck 8 s to catch the motorcycle.
(B) Using the equation of the position of the motorcycle, we can calculate the traveled distance in 8 s.
x = v · t
x = 20 m/s · 8 s
x = 160 m
(C) Now, we use the velocity equation at time 8 s.
v = v0 + a · t
v = 0 m/s + 5 m/s² · 8 s
v = 40 m/s
Burning wood would be the answer
Answer:
Is the equation for Ec=1/2 m(Dv)^2 where Dv is the difference between the angular speed & the areolar speed?
