Bài 1: Một con lắc đơn dao động điều hòa tại nơi có gia tốc g = 9,86 (m/s2). Trong 1 phút 30 giây con lắc thực hiện được 90 dao động toàn phần. a. Tính tần số dao động của con lắc.
b. Tính chiều dài của con lắc đơn.

Classify each possible hypothesis about a medicinal aloe vera plant as falsifiable or non-falsifiable. aloe vera gel is the best natural skin moisturizer. aloe vera gel can heal wounds by boosting cell renewal. aloe vera juice tastes better than carrot juice. drinking aloe juice can reduce the risk of lung cancer.

Complete the statement about memory improvement. ( )involves organizing and breaking down information into easier groups to expand capacity. rehearsal is the verbal repetition of information. these techniques are especially important for the improvement of ( ) memory.

Alinearly polarized electromagnetic wave has an average intensity of 196 w/m^2. this wave is directed towards two ideal polarizers (in real polarizers, transmission is also effected by reflection and absorption). polarizer a is oriented with its transmission axis at an angle of θ_1=20.8∘ with the incident electric field. polarizer b has its axis at an angle of θ_2=63.0∘ with the incident electric field. what is the average intensity of the wave after it passes through polarizer a? what is the average intensity of the wave after it passes through polarizer b? suppose that the two polarizers a and b are interchanged. what would the average intensity be after passing through both polarizers?