A student is observing an object of unknown mass oscillating horizontally at the end of an ideal spring. The student measures the period of oscillation with a stopwatch. The student wishes to determine the spring constant using the period measurements. Which of the following pieces of lab equipment would provide another measured quantity that provides sufficient information to complete the determination of the spring constant? a. Meterstick
b. Motion sensor
c. Balance
d. Photogate

Find the momentum for a 2.6-kg brick parachuting straight downward at a constant speed of 8.4 m/s .

The first law of thermodynamics states that heat added to a system is neither created nor destroyed but is transformed ⇒ as it changes into other forms of energy.

Unpolarized light falls on two polarizer sheets whose transmission axes are at right angles. a third polarizer is placed between the first two so that its axis makes a 52-degree angle with the axis of the first polarizer. a) what fraction of the incident light intensity is transmitted through the first polaroid? b) what fraction of the incident light intensity is transmitted through the second polaroid? c) what is the angle of polarization of the light that enters the third polaroid? d) what fraction of the incident light intensity is transmitted through the third polaroid. e) what happens if the middle polaroid is removed?