Answer:
1.
Firstly removing off one strip and it leaves electrons behind, so the strip becomes positively charged.
2. The roll however is not negatively charged because it is "earthed " by the hand holding it, thus excess negatives repel each other away through the hand.
3.Tearing off the next strip and once more it leaves electrons behind, the new strip is also positively charged and will repel the first strip.
4. Then, tear two strips apart and one will leave electrons behind on the other. Meaning that one strip is positive and the other is negative and they will attract each other.
Answer:
beta particles
Explanation:

Given mass = 14.0 g
Molar mass = 137 g/mol

According to avogadro's law, 1 mole of every substance weighs equal to its molecular mass and contains avogadro's number
of particles.
1 mole of cesium contains atoms =
0.102 moles of cesium contains atoms =
The relation of atoms with time for radioactivbe decay is:

Where
=atoms left undecayed
= initial atoms
t = time taken for decay = 3 minutes
= half life = 30.0 years =
minutes
The fraction that decays : 
Amount of particles that decay is = 
Thus
beta particles are emitted by a 14.0-g sample of cesium-137 in three minutes.
Answer:
Hence, work done= 287.54 J
Explanation:
Given data:
angle of ramp with the ground θ =20°
force applied = 76 N
work done on the crate to slide down 4 m down the ramp
W= F×d cosθ ( only the cos component of the force will slide the crate down)
W= 76×4×cos20= 287.54 J
Answer:
g = 0.905 gE
W = 67.9 N
Explanation:
given data
mass of Venus mv = 81.5% = 0.815
radius Rv = 94.9% = 0.949
weighs W = 75.0 N
solution
we apply here acceleration due to gravity at earth surface that is
g =
= 9.80 m/s² ............1
so
g =
g = 0.905 gE
and
W = m gv
W = 0.905 m gE
W = 0.905 × 75
W = 67.9 N
It is required an infinite work. The additional electron will never reach the origin.
In fact, assuming the additional electron is coming from the positive direction, as it approaches x=+1.00 m it will become closer and closer to the electron located at x=+1.00 m. However, the electrostatic force between the two electrons (which is repulsive) will become infinite when the second electron reaches x=+1.00 m, because the distance d between the two electrons is zero:

So, in order for the additional electron to cross this point, it is required an infinite amount of work, which is impossible.