PHYS 201 TEST #1 9/14/16 Dr. Holmes NAME:

DO ALL EIGHT PROBLEMS. THE
WORTH OF EACH PART OF EACH PROBLEM IS MARKED NEXT TO THE SLOT FOR THE ANSWER.
SHOW YOUR WORK FOR PARTIAL CREDIT.

1) a) What is your height in
feet and inches?

b) What is it in centimeters?

c) c)
Express 10 meters/second in miles per hour: (8.0 m/s is a runner who can do the
100 m dash in 10 seconds)

**22.4 mph.**

2)
What angle does a dime make when viewed from 40 cm away from
the eye (about an arm’s length) given that the diameter of the dime is 1.8 cm?

a) in degrees: **2.58 ^{o}**;

b) in radians **0.045
radians**;

c) in revolutions: **0.00716
revs**

d) Is this angle [smaller than, the
same as, or larger than] the angle than the moon makes when viewed from the
earth (which is 0.5^{o})

**Larger
than.**

3) a) Convert the following
vector (-28_{ }cm, 18 cm) from rectangular to polar form:

**(33.3 cm, 147.3 ^{o})**

b) Convert the
following vector: (42_{ }m, 1234°) from polar to rectangular form:

**(-29.2 m, 30.2 m)**

4) Add the following three
vectors and express your answer in POLAR form:

A = ( 7 m, 50°)

B = (12 m, 130°)

C = ( 6 m, 210°)

**(14.3 m, 126.0 ^{o})**

Draw a quick picture showing
vectors A, B, and C; also show the resultant vector and label it R:

5) A
runner runs a 1 mile race in 6 minutes even.

What is the person’s average
velocity during that time:

a) in miles/hour:

**10 mph.**

b) in m/s:

**4.46 m/s.**

c) At this average speed, how
long would it take the runner to run 100 meters?

**22.4 seconds**

d) At this average speed, how long would it take
the runner to run a marathon (26 miles)?

**156 minutes = 2 hours and
36 minutes = 9,360 seconds.**

6) To the right is a graph of v(t). On
the graphs below it, sketch x(t) and a(t) assuming that x_{o}<_{ }0.

7) Given the following
velocity data:

v(0 sec.) = -3 m/s

v(1 sec.) = 0 m/s

v(2 sec.) = +4 m/s

v(3 sec.) = +9 m/s

and given that x_{o}
= -3 meters;

a) What is the average
acceleration between t = 2 seconds and t = 3 seconds?

**5 m/s ^{2};**

b) What is the position at t
= 3 seconds?

**+4.0 meters.**

8) An object is
thrown upwards with an initial velocity of 34 m/s from the top of a building
that is 9 meters high.

a) How high (measured from the ground) does
the object reach at its highest point (ignoring air resistance and assuming
constant acceleration due to gravity)?

**67.98 m.**

b) How long will it take the object to reach
that height?

**3.47 seconds**

c) How
long will it take the object to finally reach the ground (as measured from when
the object was initially thrown)?

**6.66 s.**