Answer: a) when the cross section is doubled the resultant resistence is a half. This means the thicker wire have half resistence than the thinner wire.
Explanation: In order to explain this behaviur we have to consider the expresion for the resistence which is given by:
where L and A are the length and the cross section for the wire, respectively.
From this expresssion we can conclude the above, this means
R=εo*L/A if A is now 2A we have
R' = εo*L/2*A= R/2
The river provides fertile soil for farming
Answer:
W = 0
Explanation:
We are given with, a construction worker is carrying a load of 40 kg over his head and is walking at a constant velocity. He travels a distance of 50 m.
The work done by an object is given by :
F = ma
So,
m is mass
a is acceleration
d is displacement
The worker is moving with constant velocity, its acceleration will be 0. So, the work done by the worker is 0.
Answer: a) Twice Chuck's
Explanation:
If the angular speed is constant, as the merry - go -round is a rigid body, so the distance between two points must remain the same, it is needed that the points farther the center, move faster than the ones closer to it.
There exists a relationship between tangential and angular speed, as follows, that relates the definitions of linear and angular speed, and the angle definition:
angle = arc / radius ⇒ Δθ/Δt = Δs/Δt / r ⇒ ω = v/r ⇒ v = ω. r
If ω is constant, v is directly proportional to r, distance to the center (radius in a circular platform), so if r is twice for Andrea, her tangential speed must be twice Chuck's.
