Answer:
potential energy = mgh
= 400÷1000 × 10× 4÷100
= 0.4 × 10 × 0.04
=4/10 ×10×4/100
= 4/10 × 4/10
=16/100
= 0.16 joules
m1 (400) stretches 4cm
m1 (100g) stretches 1cm
so, m2(800g) stretches 8 cm
potential energy of m2 = mgh
= 800/1000 ×10×8/100
= 0.8 × 0.8
=8/10 ×8/10
= 64/100
=0.64 joules
Ratio of s1 to s2
16/100 ÷ 64/100
= 1:4 ( answer)
Q = magnitude of charge on each of the two point charge = 3.60 mC = 3.60 x 10⁻³ C
r = distance between the two point charges = 9.3 cm = 0.093 m
k = constant = 9 x 10⁹ Nm²/C²
F = magnitude of the force between the two point charges = ?
according to coulomb's law , force between two charges is given as
F = k Q²/r²
inserting the values
F = (9 x 10⁹) (3.60 x 10⁻³)²/(0.093)²
F = 1.35 x 10⁷ N
Answer:

Explanation:
F = Magnetic force = 4.11 N
= Net current
= Current in one of the wires = 7.68 A
B = Magnetic field = 0.59 T
= Angle between current and magnetic field = 
= Length of wires = 2.64 m
= Current in the other wire
Magnetic force is given by

Net current is given by

The current I is
.
Looks like you need to review through the lesson and take notes as it tells you in the lesson what each of these are.
Wavelength = 600 nm = 600 × 10^(-9)
speed of light = c = 3 × 10^8
planck constant = h = 6.63 × 10^(-34)
energy of photon = hc/wavelength
= 6.63 × 10^(-34) × 3 × 10^8/600 × 10^(-9)
= 1.9 × 10^(-25)/6 × 10^(-7)
= 0.31 × 10^(-16)
= 3.1 × 10^(-17)