mastering physics chapter 1 hw

A bird flies 2.8 due west and then 2.7 due north. Another bird flies 2.7 due west and 2.8 due north. What is the angle between the net displacement vectors for the two birds?

2.1 degrees you need to draw this problem out to visualize it: draw the two triangles (they overlap) -the net displacement vector is the sum of the displacement vectors that make it up (AKA the hypotenuse of each triangle) in a different color pen, start from the origin and connect the two hypotenuses, you need to find this angle (angle nearest origin) for each triangle, find the angle inside the triangle nearest the origin: 1. tan-1(2.7/2.8)= 43.96 degrees 2. tan-1 (2.8/2.7)=46.04 degrees subtract 46.04-43.96 2.08 degrees= 2.1 degrees

What is the approximate height of the average adult in centimeters?

200 cm

Find the value of 15.0 Newton in pounds

3.37 lb (15 Newton/1)(1 kg m/s^2)(1 slug /14.59 kg)(1 Lb/.3048 slug m/s^2) = 3.37

Estimate the average speed with which the hair on your head grows.

30 micrometers/hr hair grows at 1 inch per month. (1 in/1 month) X (2.54 cm/1 in) X (10^-2 m/ 1 cm) X (1 month/ 30 days) X (1 day/ 24 hours) X (1 hr/ 3600 s) = 9.8 X 10^-9 m/s (9.8 X 10^-9 m/ 1 second) X (10^6 micrometers/ 1 meter) X (3600 s/ 1 hr) = 35 micrometers/hr

A large passenger aircraft accelerates down the runway for a distance of 3300 m before leaving the ground. It then climbs at a steady 6.3 degree angle.After the plane has traveled 3200 m along this new trajectory, how high is it?

350 m the distance 3300 m is irrelevant to this part of the problem. a right triangle is formed, 3200 m is its hypotenuse (plane climbs for 3200 m). you have the angle 6.3 degrees and need to solve for the triangle's height (X) sin 6.3 = X/3200 X= (sin 6.3)(3200)= 351 m

A car travels along a straight east-west road. A coordinate system is established on the road, with increasing to the east. The car ends up 18 west of the intersection with Mulberry Road.

5 miles East

How far horizontally is it, from its initial position?

6500 m this forms a new right triangle with bottom 6500 m (3300+3200=6500), height of 350 m. solve for hypotenuse 6500^2 + 350^2 = X^2 42372500= X^2 X= 6509 m

If the entire population of the United States forms a human chain by holding hands, how many times can such a chain be wrapped around the earth's equator? Round your answer to the nearest integer.

7 times assuming: earth's circumference= 4 X 10^7 meters 300 million people in the United States (3X10^8) average palm-to-palm distance as one meter. length of human chain: (3X10^8 people)(1 meter each)= 3X10^8 meters chain divided by earth's circumference: ( 3X10^8) / (4X10^7) = 7.5 times However, in this part any answer between 5 and 15 is considered correct—after all, we are just estimating.

Approximately what is the mass of the average adult in kilograms?

80 kg

How many times does your heart beat during your lifetime? Round the answer to the nearest power of 10 and then express your answer as the order of magnitude.

answer is magnitude of 9 (72 beats/1min)(60min/1 hr)(24hr/1day)(365 days/1 yr)(75yrs/1lifetime)= 2,838,240,000= 2.8X10^9

How much would it cost to cover the entire land area of United States (including Alaska and Hawaii) with dollar bills?

area of USA= 4,461,328 mi^2 area of dollar bill= 16.0254 in^2 convert in^2 to mi^2 (16.054 in^2)(1mi^2 /4014489600 in^2)=3.99X10^-9 mi^2 divide area of USA by area of dollar (4,461,328 mi^2) / (3.99X10^-9 mi^2) =1X10^15 dollars

What would be the cost to each person in the United States given that the total cost is 9X10^14 dollars?Express your answer to one significant figure.

ave US population= 315,901,000 people 9X10^14 dollars/ 315,901,000 people = 2848994 = 3X10^6 dollars/person