Exam 1 1303 Pag

Physics 1303/1403 Professor Olness

EXAM 1 September 21, 1999

1)
(20 Points) Professor Einstein takes a trip. The first leg of his
journey, he travels: A is15km 30 degrees West of North; B is 10km 60
degrees West of South, C is 5km 45 degrees South-East, Find the
components of the total displacement vector D. Find the magnitude of
the total displacement vectorD. Find the angle of D in degrees** .
**Sketch the total trip on the plot.

2)
(20 Points) Troy's sister throws a football at a velocity of 60m/s
at an angle of 20 degrees from a cliff that is 400m high. a) Find the
time the ball is in the air. b) (5 Points) Find the total horizontal
distance covered. c) (5 Points) Find maximum vertical height __above
the cliff__.

3)
(20 Points) You are given the information listed in the table and on
the plots. Your mission is to fill in the empty entries, __and__
plot each quantity. *(Be sure and label the graphs so I can see
real numbers. Each grid unit need not be 1 unit.)*

**4a)**
(12 Points) Fill in the following table. C= A-B. (Warning, this is
subtraction!!!)

A_{X}= A_{y}= |A|= q_{A}=

B_{X}= B_{y}= |B|= q_{B}=

C_{X}= C_{y}= |C|= q_{C}=

**4b)**
(8 Points) In Dallas, the speed of the rotating earth is
approximately 700 miles per hour, or approximately 350m/s. The radius
of the earth is R_{E}=6,400Km.

· Compute the radial acceleration in MKS units

· Compare this with "g." That is, compute a/g

**5)**
(20Points) A soda jerk slides a root beer float down the counter,
but misses the customer.

The float slides off the end of the
horizontal counter (height 1meter), and hits the floor a horizontal
distance of 4 meters from the edge of the counter.

a) (10Points) What was the speed of the float when it left the counter.

b) (10Points) What is the velocity of the float just before it hits the floor.

* (I
want a magnitude and direction (angle) of the velocity vector.)*

**6)**
(20Points) True or False? Circle the correct answer. (2 points
each).

1) A and B have different dimensions. The following quantity IS physically meaningful? A+B

2) A and B have different dimensions. The following quantity IS physically meaningful? A/B

3) A and B have different dimensions. The following quantity IS physically meaningful? B-A

4) A and B have different dimensions. The following quantity IS physically meaningful? AB

It is possible to use {length, density, time} as fundamental units instead of {length, mass, time}.

6) Average velocity and instantaneous velocity are always the same value.

7) If the acceleration is zero, the velocity must be zero.

8) If the acceleration is constant, the velocity must be zero.

9) If the velocity is zero, the acceleration must be zero.

10) If the velocity is positive, the acceleration must be positive.