physics Mid-term1

the SI base unit of length is the

meter

Units obtained by combining SI units are called

Derived units

is the mass per unit volume of a material

density

Which of the following is equivalent to 4.5 m

450cm

f a woman weighs 125 lb, her mass expressed in kilograms is x kg, where x is

less then 125

If a box is 1 m high, 2.5 m long, and 1.5 m wide, what is its volume?

3.75m³

A(n) __________ is an exact quantity that people agree to use for comparison.

standard

f a tree is 15 m tall, its height expressed in feet is x ft, where x is

greater than 15.

T/F When adding two numbers, the number of significant figures in the sum is equal to the number of
significant figures in the least accurate of the numbers being added.

false

When determining the number of significant figures in a number, zeroes to the left of the decimal
point are never counted.
A. True
B. False

true

A(n) __________ is a rule that describes a pattern in nature.

law

Round off the following to three significant figures: 0.003 141 592 6

0.00314

. If, in a parallel universe, π has the value 3.14149, express π in that universe to four significant
figures.

3.1415

When can we be certain that the average velocity of an object is always equal to its instantaneous
velocity?

only when the velocity is constant

Suppose that an object is moving with constant nonzero acceleration. Which of the following is
an accurate statement concerning its motion?

In equal times its velocity changes by equal amounts.

If the acceleration of an object is negative, the object must be slowing down.
A. True
B. False

false

If the graph of the position as a function of time for an object is a horizontal line, that object
cannot be accelerating.

true

Suppose that a car traveling to the west (the -x direction) begins to slow down as it approaches a
traffic light. Which statement concerning its acceleration in the x direction is correct?

Its acceleration is positive but its velocity is negative

An object is moving with constant non-zero acceleration along the +x-axis. A graph of the

velocity in the x direction as a function of time for this object is

a straight line making an angle with the time axis.

A ball is thrown directly upward and experiences no air resistance. Which one of the following

statements about its motion is correct?

The acceleration of the ball is downward while it is traveling up and upward while it is

Two objects are thrown from the top of a tall building and experience no appreciable air

resistance. One is thrown up, and the other is thrown down, both with the same initial speed.

What are their speeds when they hit the street?

A. The one thrown down is traveling faster.

B. The one thrown up is traveling faster.

C. They are traveling at the same speed

C traveling at the same speed

Two objects are dropped from a bridge, an interval of 1.0 s apart, and experience no appreciable

air resistance. As time progresses, the DIFFERENCE in their speeds

A. decreases.

B. increases at first, but then stays constant.

C. increases.

D. remains constant

C. increases

a=

Acceleration

v=

velocity

x=

position

Δx=

change in position

Δx=

Xf-Xi

x-component=

anything with the units being m/s (||vector||*cos/θ) horizontal direction

y-compnent=

its a vertical direction with the units m/s (||vector||*cos(θ))

v=v_o+at

key words to use this eq= undergoing constant acceleration, objects falling freely

final velocity of an object given its initial velocity, acceleration, and time,

information about the time

tan(θ) =

sin(θ)/cos(θ)=opp/adj=y/x

vector calculator ex

5.4(north)*sin(40)=3.47

g=9.81m/s²

if your asked to find velocity