The Math-ter’s Tools
Which of the following relationships is INCORRECT?
A. |sin θ × cos θ| < |sin θ| + |cos θ|
B. sin θ ÷ cos θ = tan θ
C. tan 90° is undefined
D. sin θ = sin (90° – θ)
D. sin θ = sin (90° – θ)
A firefighter jumps horizontally from a burning building with an initial speed of 1.5 m/s. At what time is the angle between the firefighter's velocity and acceleration vectors the greatest?
A. The instant the firefighters jumps
B. When the firefighter reaches terminal velocity
C. Halfway through the firefighter's fall?
D. Right before the firefighter lands on the ground
A. The instant the firefighters jumps
Give me the expression of Watts, Acceleration, Velocity, and Joules in base units.
Answer on slides
Which of the following quantities is NOT a vector?
A. Velocity
B. Force
C. Displacement
D. Distance
D. Distance
What are the three kinematic equations?
1.) vf = v0 + at
2.) xf = x0 + v0t + 1/2at2
3.) vf2 = v02 + 2ax
((750 x 102)(0.1 x 10-2))/(0.003 x 104)
25 x 10-1
A car is traveling at 40 km/hr and the driver puts on the brakes, bringing the car to rest in a time of 6 s. What is the magnitude of the average acceleration of the car?
A. 240 km/hr2
B. 12,000 km/hr2
C. 24,000 km/hr2
D. 30.000 km/hr2
C. 24,000 km/hr2
Coulomb's Law is F = k (q1q2)/r2.
What are the units for the Coulomb constant, k?
*Hint: if nobody gets it I'll put up answer choices*
(N . m2)/C2
Which of the following is NOT a scalar quantity?
a.) Power
b.) entropy
c.) Work
d.) Momentum
d.) Momentum
Which of the following is NOT true regarding an object undergoing projectile motion at or near the surface of the earth?
a.) At the top of the trajectory. Both horizontal and vertical velocity must equal zero
b.) The object acceleration is always directed downwards
c.) The object horizontal and vertical motion are independent of one another
d.) Increasing the object’s vertical velocity component while keeping the horizontal constant increases its range
a.) At the top of the trajectory. Both horizontal and vertical velocity must equal zero
((400)1/2)/((4.9 x 10-5)1/2)
D. 2.9 x 103
A 20m wide river is running south to north with a speed of 5m/s. A man who can normally swim in still water with a speed of 3m/s attempts to cross by swimming perpendicular to the stream. How long does it take him to get across?
How far downstream is he when he reaches the other side compared to where he started?
6.67 seconds and 33 meters
Give me two ways to express the units for resistance, ohms.
*Hint: V = IR*
Volts/Amperes
(J . s)/C2
What are the x- and y-components respectively of the following vector?
a.) 25m and 43.5m
b.) 43.5m and 25m
c.) 20m and 30m
d.) 30m and 20m
a.) 25m and 43.5m
a.) What is the displacement of the object described in the figure from t = 2s to t = 12s?
b.) At which of the following times is the velocity of the object depicted in the figure zero?
c.) At which of the following times if the object depicted in the figure moving in reverse?
d.) At which of the following times is the object depicted in the figure moving with the highest speed?
a.) -6
b.) t = 5s
c.) t = 7s
d.) t = 7s
(1/0.82) + (1/0.02) + (1/0.21)
55.98
A physics major builds a potato launcher and tests it in an open field. The student launches a potato with a velocity of 12 m/s at an angle of 30o. The potato is found 60 meters from the launch site. Which of the following represents the maximum height achieved by the potato?
A. 0.3 m
B. 1.8 m
C. 5 m
D. 18 m
B. 1.8 m
Which of the following expression correctly illustrates the SI base units for each of the variables in the formula below?
mΔv = FΔt
A. lb x mph = ft x lb x s
B. kg x m/s = N x s
C. kg x m/s = (kg⋅m)/s2 x s
D. g x m/s = (g⋅m)/s2 x s
C. kg x m/s = (kg⋅m)/s2 x s
Which of the following most accurately represents the resultant vector u - v? (Pull up slide)
D
The diagram below shows two vectors.
If a student uses the formula ab . sin(60o), where a and be are the magnitude of the respective vectors A and B, then which of the following best describes the computed value?
a.) Positive scalar
b.) Negative scalar
c.) Vector into the page
d.) Vector out of the page
d.) Vector out of the page
(log (8 x 102) x log (0.002))/ (-log (0.009))
A. -5.32
B. -3.82
C. 1.02
D. 4.26
B. -3.82
A man runs 100 meters in a straight path over 10 seconds. He then runs halfway back to his starting position in 5 seconds. What is the difference between the man's average velocity and his average speed?
A. 3.3 m/s
B. 5 m/s
C. 6.7 m/s
D. 15 m/s
C. 6.7 m/s
A student calculates kinetic energy using the expression 1/2mv2. If mass is measured in grams and velocity in centimeters per second, what are the resulting units of kinetic energy, and how would you convert them to joules?
107 (g cm2)/s2
Which of the following vector combinations will result in the greatest displacement?
a.) e - b
b.) b - d
c.) e + d
d.) a -c
c.) e + d
A train suddenly brakes, taking 60 s to come to a halt while traveling 1000 m at constant acceleration. Is it possible to determine the speed of the train prior to applying the brakes?
A. No, because only the average velocity while braking can be found.
B. No, because velocity cannot be found only knowing acceleration.
C. Yes, because the distance traveled can be divided by time.
D. Yes, because the initial speed is equal to double the average speed while braking.
D. Yes, because the initial speed is equal to double the average speed while braking.