10. [0/2 Points] DETAILS PREVIOUS ANSWERS OSCOLPHYS2016 2.3.WA.007. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A woman drives a car from one city to another with different constant speeds along the trip. She drives at a speed of 75.0 km/h for 20.0 min, 95.0 km/h for 25.0 min, makes a stop for 35.0 min, then continues at 40.0 km/h for 30.0 min, at which point she reaches her destination. (a) What is the total distance between her starting point and destination (in km)? X To find the total distance, you will need to find the distance for each segment of the trip. How is distance related to speed? Also, be sure to check your unit conversions. km (b) What is the average speed for the entire trip (in units of km/h)? X Note that the average speed for the whole trip depends on the total distance covered and the total time. Also be sure to check your unit conversions. km/h Additional Materials Reading Submit Answer 11. [0/2 Points] DETAILS PREVIOUS ANSWERS OSCOLPHYS2016 2.3.WA.009. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A particle moves in one dimension, and its position as a function of time is given by x = (1.7 m/s)t + (-3.6 m/s2)+2. (a) What is the particle's average velocity from t = 0.45 s to t = 0.55 s? (Indicate the direction with the sign of your answer.) X Average velocity is the change in position over change in time. Think about how to use the function to find the change in position. m/s (b) What is the particle's average velocity from t = 0.49 s to t = 0.51 s? (Indicate the direction with the sign of your answer.) X Average velocity is the change in position over change in time. Think about how to use the function to find the change in position. m/s Additional Materials La Reading8. [0/1 Points] DETAILS PREVIOUS ANSWERS OSCOLPHYS2016 2.3.P.013. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Conversations with astronauts on the lunar surface were characterized by a kind of echo in which the earthbound person's voice was so loud in the astronaut's space helmet that it was picked up by the astronaut's microphone and transmitted back to Earth. It is reasonable to assume that the echo time equals the time necessary for the radio wave to travel from the Earth to the Moon and back (that is, neglecting any time delays in the electronic equipment). Calculate the distance from Earth to the Moon (in km) given that the echo time was 2.58 s and that radio waves travel at the speed of light (3.00 x 10 m/s). X km Additional Materials Reading Submit Answer 9. [-/2 Points] DETAILS OSCOLPHYS2016 2.3.P.015. MY NOTES ASK YOUR TEACHER The planetary model of the atom pictures electrons orbiting the atomic nucleus much as planets orbit the Sun. In this model you can view hydrogen, the simplest atom, as having a single electron in a circular orbit 1.06 x 10 10 m in diameter. (a) If the average speed of the electron in this orbit is known to be 2.20 x 10 m/s, calculate the number of revolutions per second it makes about the nucleus. revolutions/s (b) What is the electron's average velocity (in m/s)? (Assume the electron completes one revolution.) m/s Additional Materials Reading4. [1/2 Points] DETAILS PREVIOUS ANSWERS OSCOLPHYS2016 2.3.P.006. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A helicopter blade spins at exactly 90 revolutions per minute. Its tip is 6.00 m from the center of rotation. (a) Calculate the average speed (in m/s) of the blade tip in the helicopter's frame of reference. 3,140 x m/s (b) What is its average velocity (in m/s) over one revolution? 0 m/s Additional Materials Reading 5. [0/1 Points] DETAILS PREVIOUS ANSWERS OSCOLPHYS2016 2.3.P.007. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER The North American and European continents are moving apart at a rate of about 3 cm/y. At this rate how long will it take them to drift 360 km farther apart than they are at present? .2 x y Additional Materials Reading 6. [-/1 Points] DETAILS OSCOLPHYS2016 2.3.P.010. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Tidal friction is slowing the rotation of the Earth. As a result, the orbit of the Moon is increasing in radius at a rate of approximately 4 cm/year. Assuming this to be a constant rate, how many years will pass before the radius of the Moon's orbit increases by 8.83 x 100 m (2.3%)? years2. [1/3 Points] DETAILS PREVIOUS ANSWERS OSCOLPHYS2016 2.1.WA.001. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A truck travels due east for a distance of 1.3 km, turns around and goes due west for 7.1 km, and finally turns around again and travels 2.9 km due east. (a) What is the total distance that the truck travels? 12.6 x The question asks for the total distance traveled, regardless of direction. km (b) What are the magnitude and direction of the truck's displacement? 5.0 magnitude X Displacement is the change in position, that is, the difference between the initial and final position. km direction west v V Additional Materials Reading 3. [1/2 Points] DETAILS PREVIOUS ANSWERS OSCOLPHYS2016 2.3.P.005. MY NOTES ASK YOUR TEACHER (a) Calculate Earth's average speed (in m/s) relative to the Sun. 3 x m/s (b) What is its average velocity (in m/s) over a period of one year? 0 m/s Additional Materials Reading