Question

version -01 - unit 2: quest 3: speed and velocity
this print - out should have 6 questions. multiple - choice questions may continue on the next column or page - find all choices before answering.
001 10.0 points
hewitt cp9 03 p01 97785
the oceans level is currently rising at about 1 mm per year.
at this rate, in how many years will sea level be 5 m higher than now?
answer in units of y. answer in units of y.
002 10.0 points
holt sf 02a 01 97808
heather and matthew walk eastward with a speed of 0.96 m/s east.
if it takes them 39 min to walk to the store, how far have they walked?
answer in units of km. answer in units of km.
003 10.0 points
light from the sun 97813
light from the sun reaches earth in 8.3 min.
how far is the earth from the sun? the velocity of light is 3×10^8 m/s.
answer in units of m. answer in units of m.
004 10.0 points
holt sf 02rev 11 232981
the olympic record for the marathon is 2 h, 9 min, 21 s.
if the average speed of a runner achieving this record is 5.436 m/s, what is the marathon distance?
answer in units of km. answer in units of km.
005 10.0 points
constant velocity 01 79665
at 1:00 p.m. a car, traveling at a constant velocity of 98 km/h toward the west, is 16 km to the west of our school.
how far from the school will it be at 3:30 p.m.?
answer in units of km. answer in units of km.

Explanation:

001

Step1: Convert units

We know that $1\ m = 1000\ mm$. So, $5\ m=5\times1000 = 5000\ mm$.

Step2: Calculate the number of years

The rate of sea - level rise is $r = 1\ mm/y$. Let the number of years be $t$. Using the formula $d=rt$ (where $d$ is the distance), we have $t=\frac{d}{r}$. Substituting $d = 5000\ mm$ and $r = 1\ mm/y$, we get $t=\frac{5000\ mm}{1\ mm/y}=5000\ y$.

Step1: Convert time to seconds

We know that $1\ min=60\ s$. So, $t = 39\ min=39\times60\ s=2340\ s$.

Step2: Use the formula $d = vt$

The speed $v = 0.96\ m/s$. Using the formula $d=vt$, we substitute $v = 0.96\ m/s$ and $t = 2340\ s$. So, $d=0.96\ m/s\times2340\ s = 2246.4\ m$.

Step3: Convert distance to kilometers

Since $1\ km = 1000\ m$, then $d=\frac{2246.4\ m}{1000}=2.2464\ km$.

Step1: Convert time to seconds

We know that $1\ min = 60\ s$. So, $t=8.3\ min = 8.3\times60\ s=498\ s$.

Step2: Use the formula $d = vt$

The speed of light $v = 3\times10^{8}\ m/s$. Using the formula $d = vt$, we substitute $v = 3\times10^{8}\ m/s$ and $t = 498\ s$. So, $d=(3\times10^{8}\ m/s)\times498\ s=1.494\times10^{11}\ m$.

Answer:

$5000$

002