Answer:d
Explanation:
From Gauss law Electric field inside a surface is directly proportional to the charge enclosed in it.
Electric field inside a spherical shell is zero and hence there is no charge inside the spherical shell because q charge induces a -q charge on inside surface of spherical shell.
and to counter it there is q charge on the surface. So total charge outside the surface is Q+q
Group one on the periodic table, also known as the alkali metals, all:
- form ions with a charge of +1
- display similar extreme chemical behaviour
- have typical metallic properties
- are far too reactive to be found naturally in their pure forms
Answer:
Fscos63
Explanation:
Given that a horizontal pole is attached to the side of a building. There is a pivot P at the wall and a chain is connected from the end of the pole to a point higher up the wall. There is a tension force F in the chain. What is the moment of the force F about the pivot P?
Taking the moment from the pivot point P, that means the moment at point p = 0
Then, if we consider the weight mg of the pole, according to the principle of equilibrium : sum of the upward forces equal to the sum of the downward forces.
Therefore, mg = Fsinø ....... (1)
Also, taking moment at point P
Let the length of the pole = s
The length of the weight of the pole = 1/2 S
Fscosø = mgs/2
The distance s will cancel out
2Fcosø = mg ...... (3)
Substitute mg in equation 1 into equation 3
2fcosø = fsinø
F will cancel out
Tanø = 2
Ø = tan^-1(2)
Ø = 63.4 degree
The moment of force F about pivot point P will be
Moment = force × distance
Moment = Fcos63 × S
Moment = Fscos63
Assuming g = 10, the weight of the sled is 720N.
If it takes 26.5N to just pull the sled, then the frictional force f is 26.5N in the opposite direction.
f = μ*720N
26.5N = μ*720N
μ = 26.5N/720N = 0.037 (2 s.f.)
