When doing unit conversions, you need a relation between the two units. For instance, in converting from millimeters to meters, you need to know that
1m=1000mm.
Once you know this, you need to divide one side by the other to obtain a ratio of m to mm:
1=1m1000mm.
If you are converting from millimeters to meters, then this is the proper ratio. It has mm in the denominator, so that it will cancel the units of the quantity that you are converting. For instance, if you were converting 63mm, then you would have
63mm⋅1m1000mm=0.063m.
If you were converting a quantity from meters to millimeters, you would use the reciprocal ratio:
1=1000mm1m.

Item #2 A.)
Suppose that you measure a pen to be 10.5 cm long. Convert this to meters.
Express your answer in meters.

Item #4 A.)
Velocity differs from speed in that velocity indicates a particle's __________ of motion.
Enter the letter from the list given in the problem introduction that best completes the

B.)
Unlike speed, velocity is a __________ quantity.
Enter the letter from the list given in the problem introduction that best completes the sentence.

C.)
A vector has, by definition, both __________ and direction.
Enter the letter from the list given in the problem introduction that best completes the sentence.

D.)
Once you have selected a coordinate system, you can express a two-dimensional vector using a pair of quantities known collectively as __________.
Enter the letter from the list given in the problem introduction that best completes the sentence.

E.)
Speed differs from velocity in the same way that __________ differs from displacement.
Enter the letter from the list given in the problem introduction that best completes the sentence.

Item #5
A.)
Where is the particle at t = 0?
Express your answer using two significant figures.

Item #9)

A bullet traveling horizontally at a speed of 370m/s hits a board perpendicular to its surface, passes through and emerges on the other side at a speed of 230m/s .

If the board is 4.00cm thick, how long does the bullet take to pass through it?

Item #10)
A rifle bullet with a muzzle speed of 340m/s is fired directly into a special dense material that stops the bullet in 22.0cm .

Assuming the bullet’s deceleration to be constant, what is its magnitude?

2a: .105 m

4b: vector
4c: magnitude
4e: distance

for the rest of #4, it might help if you posted the fill-in-the-blank options

This post was edited by TritonV8 on Nov 1 2013 05:12pm

hey, can you explain to me how you get the answers too?i want to learn as well..

5a should have a drawing, equation, or figure with it

all the problem #4 answers are just definitions, so you should read them from the book.
for #2, all you do is shift the decimal place left or right, depending on how you convert the units. to convert from cm to m, you just move the decimal place 2 spots to the left. So 10.5 cm is equal to .105 m

9) board is 4cm thick or 0.04m thick, this is what we use as d, distance traveled in kinematics equations

All of the eqns given where we need to solve for t involve a, so we solve for A first

Vf^2 = Vi^2 + 2AD
or

A = (Vf^2-Vi^2) / (2*0.04)
= 230^2 - 370^2 / (2(0.04)
= -1.05 x 10^6 m/s^2

our answer is negative because at the moment the bullet hits the board, its decelerrating.

Vf = Vi + at
T = (Vf - Vi) / A
= (230 - 370) / (-1.05 * 10^6)
= 1.3 * 10^-4 s

aka 4cm board isnt enough to stop a bullet (obviously) and it was only in the board for that many seconds

10)

same eqn as last one


Vf^2 = Vi^2 + 2AD
except this time we know that Vf is zero since the material stops the bullet completely

d = 0.22m that the bullet traveled

A = (Vf^2-Vi^2) / (2*0.22)
= (0-340^2) / (2*0.22)
= -11560 / 0.44
= -2.62* 10^5


again our answer is negative because vectors are in opposite directions. bullet is traveling -----> |.

| is the board. the board "pushes" back enough on the bullet to stop it.



answer asks only for magnitude not direction so its just
2.62 * 10^5

5 requries a graph

Do you have the answer for 9?

I'm pretty sure I didn't make a computational error...

Still need these.. And thanks guys
Item #2 Part B
Suppose that, from measurements in a microscope, you determine that a certain bacterium covers an area of 1.50μm2. Convert this to square meters.

Item #4 Part A
Velocity differs from speed in that velocity indicates a particle's __________ of motion.
Enter the letter from the list given in the problem introduction that best completes the sentence.

Item #4 Part G
Identify the following physical quantities as scalars or vectors.
Scalar Quantity & Vector Quantity

Choices: Position, Velocity, Displacement, Speed, Acceleration, Average velocity, Distance.

Item #5 Part A
The location of a moving particle at a particular time is given by x=at−bt2, where a = 11m/s and b = 0.70m/s2 .
Where is the particle at t = 0?
Express your answer using two significant figures.

Part B
The location of a moving particle at a particular time is given by x=at−bt2, where a = 11m/s and b = 0.70m/s2 .
What is the particle’s displacement for the time interval t1 = 2.4s and t2 = 4.2s ?
Express your answer using two significant figures.

Item #8 Part A
A sports car can accelerate from 0 to 50mi/h in 3.9s .
What is the magnitude of the average acceleration of the car in meters per second squared?
Express your answer using two significant figures.

10^6 μm =1 m
square both sides:
10^12 um^2 = 1m ^2

so 1.50μm^2 = 1.50*10^(-12) m^2

This post was edited by Azrad on Nov 2 2013 08:04am