I’LL MARK YOU BRAINIEST IF U ANSWER PLEASE 1. suppose the government passed a law saying, 'everyone must use an electric toothbrush ." use the four criteria to assess this change in the system of brushing your teeth

2. what are two methods of support used to keep a system operating safely and efficiently

3. A police system lifts a 500-N Weight A distance of 1.5m. Marina pulls the rope A distance of 9.0m, exerting a Force of 100 N.

a) what is the mechanical advantage of this pulley system

b) What input did marina do on the road

c) what useful output did the rope do on the weight

d) what is the efficiency of the pulley system

THIS IS GRADE 8 PHYSICS PLEASE ANSWER
PLEASE ANSWER AT LEAST 1

This is what a calorimeter is used for simpler ex, to measure calories in food.

Sorry i don’t know what to do

Answer: a charge of -1.0  × 10⁻⁴ c must be placed  at x = 26 m.the sign of the charge will be the same sign as the  -4.0  µc charge.======electricstatic force between two point charges  is given by    where k is coulomb's constant,  8.99×10⁹  n·m²/c², q₁ and q₂ are the point charges, and r is the distance between the two point charges.assign positive to q₁let q₁ =  6.0 µc, q₂ = -4.0  µc, q₀ represent the charge at the origin, and q₃ represent this new charge to place.the charge at the origin q₀ would experience the following force f₀₁ from q₁, with r = 6.0 m (note that 1  µc = 10⁻⁶ c)    the force from q₂    the force from q₃    the net force on the origin charge, q₀, has to be zero for no electrostatic forcehaving an equation where k and q₀ can be divided out of the equation will allow us to solve for q₃    isolating:     a charge of -1.0  × 10⁻⁴ c must be placed  at x = 26 m.the sign of the charge will be the same as the  -4.0  µc charge