Open Question
Time intervals measured with a physical stopwatch typically have an uncertainty of about 0.2 s, due to human reaction time at the start and stop moments. What is the percent uncertainty of a hand-timed measurement of 4.5 min?
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1. Intro to Physics Units
Introduction to Units
Back1. Intro to Physics Units
Introduction to Units
- Open Question
A watch manufacturer claims that its watches gain or lose no more than 9 seconds in a year. How accurate are these watches, expressed as a percentage?
1views - Open Question
Write the following as full (decimal) numbers without prefixes on the units:
(e) 22.5 nm
1views - Open Question
Express the following using the prefixes of Table 1–4: 18 x 10² bucks and
1views - Open QuestionA demented scientist creates a new temperature scale, the 'Z scale.' He decides to call the boiling point of nitrogen 0°Z and the melting point of iron 1000°Z.b. Convert 500°Z to degrees Celsius and to kelvins.1views
- Open QuestionThe lowest and highest natural temperatures ever recorded on earth are −129°F in Antarctica and 134°F in Death Valley. What are these temperatures in °C and in K?1views
- Open Question
The age of the universe is thought to be about 14 billion years. Assuming two significant figures, write this in powers of 10 in :
(a) years
1views - Open Question
The Sun, on average, is 93 million miles from Earth. How many meters is this? Express
(b) using a metric prefix (km).
1views - Open QuestionAn alien spacecraft is flying overhead at a great distance as you stand in your backyard. You see its searchlight blink on for 0.150 s. The first officer on the spacecraft measures that the searchlight is on for 12.0 ms. (a) Which of these two measured times is the proper time? (b) What is the speed of the spacecraft relative to the earth, expressed as a fraction of the speed of light c?1views
- Open QuestionThe positive muon (µ+), an unstable particle, lives on average 2.20 * 10^-6 s (measured in its own frame of reference) before decaying. (b) What average distance, measured in the laboratory, does the particle move before decaying?
- Open QuestionThe positive muon (µ+), an unstable particle, lives on average 2.20 * 10^-6 s (measured in its own frame of reference) before decaying. (a) If such a particle is moving, with respect to the laboratory, with a speed of 0.900c, what average lifetime is measured in the laboratory?
- Open Question(b) A force is applied to a particle along its direction of motion. At what speed is the magnitude of force required to produce a given acceleration twice as great as the force required to produce the same acceleration when the particle is at rest? Express your answer in terms of the speed of light
- Open QuestionA proton has momentum with magnitude p0 when its speed is 0.400c. In terms of p0, what is the magnitude of the proton's momentum when its speed is doubled to 0.800c?
- Open QuestionSuppose the two lightning bolts shown in Fig. 37.5a are simultaneous to an observer on the train. Show that they are not simultaneous to an observer on the ground. Which lightning strike does the ground observer measure to come first?
- Open QuestionX rays with initial wavelength 0.0665 nm undergo Compton scattering. What is the longest wavelength found in the scattered x rays? At which scattering angle is this wavelength observed?