Answer:
C
Sign-Negative
Explanation:
We are given that
Electric field =
(Radially downward)
Acceleration=
(Upward)
Mass of charge=3 g=
kg
1kg=1000g
We have to find the magnitude and sign of charge would have to be placed on a penny .
By newton's second law


Substitute the values then we get

Substitute the values then we get




C
Sign of charge =Negative
Because electric force acting in opposite direction of electric field therefore,charge on penny will be negative.
D. March because it is just below the 1 million marker on the graph and it is the only one that low.
Answer:
Explanation:
1. Frictional force is responsible for running of car and buses on roads.
2.Gravitational force exists between astronauts in space.
3. Magnetic for is responsible to attract the iron objects using a magnet
4.Electrostatic force is responsible for fiber to stick on the skin.This force occurs due to the presence of charge.
5.When a person is pushing a trolley then object experience a normal reaction from ground.
6.Gravitational force makes the planet to move in their orbits.
Answer:
Explanation:
Let c be the circumference and r be the radius
c = 2πr , r = c / 2π , area A = π r² = π (c/2π )² = (1/4π) x c²
flux (ψ) = BA = 1 X 1/4π X c²
dψ/dt = 1/4π x 2c dc/dt =1/2π x c x dc/dt
at t = 8 s
c = 161 - 13 x 8 = 57 cm , dc/dt = 13 cm/s
e = dψ/dt = (1 / 2π )x 57 x 13 x 10⁻⁴ = 118 x 10⁻⁴ V.