A car travelling at a constant speed of 70km/h passes a stationary police car. The police car immediately goes on the chase acce
1 answer:
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Explanation:
The resistance of a wire is given by the formula as follows :
l is length of wire
A is area of cross section,
Since, r=d/2, d = diameter
It is given in the problem that the resistance of two aluminum wires is same.
We have, L₁=2L₂
So,
So, the ratio of the diameter of the longer wire to the diameter of the shorter wire is
Answer:
c. V = 2 m/s
Explanation:
Using the conservation of energy:
so:
Mgh =
where M is the mass, g the gravity, h the altitude, I the moment of inertia of the pulley, W the angular velocity of the pulley and V the velocity of the mass.
Also we know that:
V = WR
Where R is the radius of the disk, so:
W = V/R
Also, the moment of inertia of the disk is equal to:
I =
I =
I = 10 kg*m^2
so, we can write the initial equation as:
Mgh =
Replacing the data:
(5kg)(9.8)(0.3m) =
solving for V:
(5kg)(9.8)(0.3m) =
V = 2 m/s