<span>1 cal = 4,185 J
1 kcal = 1*10^3 cal
or
=1000 cal</span>
Answer:
v = 54 m/s
Explanation:
Given,
The maximum height of the flight of golf ball, h = 150 m
The velocity at height h, u = 0
The velocity of the golf ball right before it hits the ground, v = ?
Using the III equations of motion
<em> v² = u² + 2gh</em>
Substituting the given values in the above equation,
v² = 0 + 2 x 9.8 x 150 m
= 2940
v = 54 m/s
Hence, the speed of the golf ball right before it hits the ground, v = 54 m/s
The answer should be d because they are constantly rotating
Answer with Explanation:
We are given that
Length of wire 1=![L_1](https://tex.z-dn.net/?f=L_1)
Length of wire 2=![L_2](https://tex.z-dn.net/?f=L_2)
Resistivity of copper wire=![\rho_1=1.7\times 10^{-5}\Omega-m](https://tex.z-dn.net/?f=%5Crho_1%3D1.7%5Ctimes%2010%5E%7B-5%7D%5COmega-m)
Resistivity of aluminum wire=![\rho_2=2.82\times 10^{-5}\Omega-m](https://tex.z-dn.net/?f=%5Crho_2%3D2.82%5Ctimes%2010%5E%7B-5%7D%5COmega-m)
Wire 1=Copper wire
Wire 2=Aluminum wire
Diameter of both wires are same and resistance of both wires are also same.
We know that
Resistance =![\frac{\rho l}{A}](https://tex.z-dn.net/?f=%5Cfrac%7B%5Crho%20l%7D%7BA%7D)
When diameter of wires are same then their cross section area are also same .
![l=\frac{RA}{\rho}](https://tex.z-dn.net/?f=l%3D%5Cfrac%7BRA%7D%7B%5Crho%7D)
When resistance and area are same then the length of wire depend upon the resistivity of wire .
The length of wire is inversely proportional to resistivity.
When resistivity is greater then the length of wire will be short and when the resistivity is small then the length of wire will be large.
![\rho_1](https://tex.z-dn.net/?f=%5Crho_1%3C%5Crho_2)
Therefore, ![L_1>L_2](https://tex.z-dn.net/?f=L_1%3EL_2)
Hence, the length of wire 1 (copper wire) is greater than the length of wire 2 (aluminum).
![\frac{L_1}{L_2}=\frac{\frac{RA}{1.7\times 10^{-5}}}{\frac{RA}{2.82\times 10^{-5}}}=1.66](https://tex.z-dn.net/?f=%5Cfrac%7BL_1%7D%7BL_2%7D%3D%5Cfrac%7B%5Cfrac%7BRA%7D%7B1.7%5Ctimes%2010%5E%7B-5%7D%7D%7D%7B%5Cfrac%7BRA%7D%7B2.82%5Ctimes%2010%5E%7B-5%7D%7D%7D%3D1.66)
![L_1=1.66L_2](https://tex.z-dn.net/?f=L_1%3D1.66L_2)