Option (C) is correct that the majority of the elements on the periodic table are metals.
#$# THANK YOU #$#
There are some missing data in the text of the problem. I've found them online:
a) coefficient of friction dry steel piston - steel cilinder: 0.3
b) coefficient of friction with oil in between the surfaces: 0.03
Solution:
a) The force F applied by the person (300 N) must be at least equal to the frictional force, given by:

where

is the coefficient of friction, while N is the normal force. So we have:

since we know that F=300 N and

, we can find N, the magnitude of the normal force:

b) The problem is identical to that of the first part; however, this time the coefficienct of friction is

due to the presence of the oil. Therefore, we have:
Answer:
276.5 m/s^2
Explanation:
The initial angular velocity of the turbine is

The length of the blade is
r = 17.9 m
So the centripetal acceleration is given by

At the instant t = 0,

So the centripetal acceleration of the tip of the blades is

Answer:
C
Explanation:
Formula E=F/C also E=V/d
In this case use the second formula; E=V/d
Data given; E=4N/C d=8m
So v=E X d
V=4x8=32V
k.e=eV= 2X32=64eV
the radiogenic heat produced by the radioactive decay of isotopes in the mantle and crust, and the primordial heat left over from the formation of the Earth.