Without calculating the numerical value, simplify:
Simplify:
(34⋅3-2)/3
3(4−2−1)=31 = 3
Which quantity has the same units as velocity?
A. m/s2
B. m/s
C. N/m
D. kg/s
m/s
Where am I from?
Orange County
A vector has: x>0, y<0
Which quadrant does it point toward?
Quadrant IV
An object starts with velocity v0 and accelerates at a constant acceleration a.
Which equation can directly give you its velocity after time t?
v=v0+at
Which is larger?
2+3(4)2+3(4) or (2+3)(4)
2+3(4)=14
(2+3)(4)=20 (larger)
A length is multiplied by a scale factor of 3.
By what factor does the area change?
9 because 32=9
An object has a horizontal line on a position-vs-time graph.
Is the object moving?
No because a horizontal line has slope zero.
What college am I from?
Seventh!! 7️⃣
An object has a=0
Does that necessarily mean the object is stationary?
No since it could be moving at a constant velocity.
Simplify:
(34⋅3-2)/3
3(4−2−1)=31 = 3
Suppose
d=vt
If velocity is measured in m/s and time is measured in seconds, what units must distance have?
m/s * s = m
Two objects have position-time graphs.
Which object is moving faster?
They have the same speed:
4m/s but opposite velocities.
A 20 N vector points 30∘ above the positive x-axis. Which component is larger: Fx or Fy?
Fx=20cos30∘
≈17.3N
Fy=20sin30∘
=10N
A car starts from rest and accelerates at:
3m/s2 for 4 seconds. Find its final velocity.
v=0+(3)(4)
= 12m/s
What breed is my dog?
golden retriever
A cube has side length 3 cm. Every side is doubled.
A student says:
"The volume doubles because the side length doubled."
Is the student correct?
No since volume scales cubically.
Vnew = 23Vold
8
Display a position vs. time graph with three straight-line segments:
During which segment is the object moving fastest? What is its velocity during that segment?
For Segment A:
v=8−0/2−0
=4 m/s
For Segment B:
v=0
For Segment C:
v=2−8/7−5
=−3 m/s
Compare the magnitudes:
∣4∣>∣−3∣>0|4|>|-3|>0
Therefore:
Segment A, with a velocity of +4 m/s
A vector points directly upward.
What are its x- and y-components?
x = 0, y > 0
A ball starts from rest and travels 45 m while accelerating at 5m/s2.
Which equation would be most useful for finding the time? Please solve for the time.
x=v0t+1/2at2
45=1/2(5)t2
t2=18
t≈4.24s
Solve for x:
(3x−2+5)/4=2x
3x-2 = 8x-20
18 = 5x
x = 18/5
A runner travels 100 m in 12.5 seconds.
Another runner travels 0.12 km in 14 seconds.
Who has the greater average speed?
Runner 1:
v1=100/12.5
= 8m/s
Runner 2:
0.12km=120m
v2=120/14
≈8.57m/s
Therefore:
Runner 2
A position-time graph is a straight line passing through (2,8) and (6,20).
Velocity:
v=20−8/6−2
=3m/s
Equation:
x=3t+b
Using (2,8):
8=6+b
b=2
Therefore:
x=3t+2
At t=10
x=32m
x(10)=32m
Two forces act on an object:
A=40N at 60∘ B=25N at 150∘
Find the x-component of the resultant.
Ax=40cos60∘=20
Bx=25cos150∘≈−21.7B
Therefore:
Rx=20−21.7
Rx=−1.7N
Two cars start from rest.
After the same amount of time, how do their velocities compare?
v=at
vB=2vA
So Car B has twice the velocity of Car A.