A tennis racket exerts a force of magnitude F on a tennis ball. If the mass of the tennis racket is five times the mass of the tennis ball, the magnitude of the force of the tennis ball on the tennis racket is (Hint: Newton’s 3rd Law of Motion)

What’s #16 asking and how do i solve it?

What is the freezing point of radiator fluid that is 50% antifreeze by mass? kf for water is 1.86 ∘c/m.

Aresistor with an unknown resistance is connected in parallel to a 9 ω resistor. when both resistors are connected in parallel to an emf source of 21 v, the current through the unknown resistor is measured with an ammeter to be 4 a. what is the resistance of the unknown resistor? answer in units of ω.