Answer:
Therefore the ratio of diameter of the copper to that of the tungsten is

Explanation:
Resistance: Resistance is defined to the ratio of voltage to the electricity.
The resistance of a wire is
- directly proportional to its length i.e

- inversely proportional to its cross section area i.e

Therefore

ρ is the resistivity.
The unit of resistance is ohm (Ω).
The resistivity of copper(ρ₁) is 1.68×10⁻⁸ ohm-m
The resistivity of tungsten(ρ₂) is 5.6×10⁻⁸ ohm-m
For copper:


......(1)
Again for tungsten:

........(2)
Given that
and 
Dividing the equation (1) and (2)

[since
and
]



Therefore the ratio of diameter of the copper to that of the tungsten is

Answer:
d = 39.7 km
Explanation:
initial position of the boat is 45 km away at an angle of 15 degree East of North
so we will have


after some time the final position of the boat is found at 30 km at 15 Degree North of East
so we have


now the displacement of the boat is given as



so the magnitude is given as


3) a stretched rubber band
Answer:

Explanation:
Given:
- work done to stretch the spring,

- length through which the spring is stretched beyond equilibrium,

- additional stretch in the spring length,

<u>We know the work done in stretching the spring is given as:</u>

where:
k = stiffness constant


Now the work done in stretching the spring from equilibrium to (
):



So, the amount of extra work done:


