A student performs an experiment in measuring the period of a simple pendulum of known length 49.0 cm. He performed five trials and measures the results(in second) to be :1.44,1.39,1.46,1.48,1.38.Calculate the % uncertainty to compare the measured value with the theoretical value.(Hint :Theoretical value=2I√l÷g, measured value=mean value)

Abird flies directly overhead from where you stand at an altitude of 300.0 m and at a speed horizontal to the ground of 20.0 m/s. the bird has a mass of 2.0 kg. the radius vector to the bird makes an angle \thetaθ with respect to the ground. the radius vector to the bird and its momentum vector lie in the xyxy-plane. what is the bird’s angular momentum about the point where you are standing?

Scientists follow specific processes in order to determine valid explanations and conclusions from observations. david observed strange lights in the sky above his home outside of roswell, new mexico. the only explanation that makes sense to him is that there are ufos in the area. what should david do next to verify his explanation?

Sound travels slower in colder air that it does in warmer air. make a claim about the effect of air temperature on the speed of sound. support your claim with evidence