Answers:
a)
b)
Explanation:
a) We can solve this knowing the angular momentum is conserved, then:
(1)
Where:
is the initial moment of inertia of the system
is the initial angular velocity
is the final moment of inertia of the system
is the final angular velocity
But first, we have to find and :
(2)
(3)
Where:
is the student's moment of inertia
is the mass of each object
is the initial radius
is the final radius
Then:
(4)
(5)
Substituting the results of (4) and (5) in (1):
(6)
Finding :
(7) This is the final angular velocity
b) The rotational kinetic energy is:
(8)
The change in kinetic energy is:
(9)
Since we already calculated these values, we can solve (9):
(10)
Finally:
Explanation:
Resistance = Resistivity * Length / Area
= 30 * (1/3) / (1/4)
= 40x.
Hence the resistance of the constant wire is 2 * 40 = 80 ohms.
Answer:
By nature, laws of Physics are stated facts which have been deduced and derived based on empirical observations. Simply put, the world around us works in a certain way, and physical laws are a way of classifying that “working.”
Answer:
The horizontal range will be
Explanation:
We have given initial speed of the shell u =
Angle of projection = 51°
Acceleration due to gravity
We have to find maximum range
Horizontal range in projectile motion is given by
So the horizontal range will be
Answer:
The voltage across an 9.07-nm-thick membrane if the electric field strength across it is 8.76 MV/m is 0.079 V
Explanation:
Given
Electric field (E) = 8.76 MV/m = 8.76 * V/m
Thick of the membrane = 9.07 nm = 9.07 * m
Potential difference between uniform electric field plates
ΔVab = Ed
ΔVab = 8.76 * V/m * 9.07 * m = 0.079 V