General
Kinematics
Dynamics
Waves
Electricity
100
Describe a vector measurement, and include its two properties.
Vectors are measurements with magnitude and direction.
100
Describe the significance of the slope of a displacement vs time graph.
The slope of a displacement vs. time graph measures velocity.
100
Describe the difference between mass and weight.
Mass is an intrinsic scalar property of matter and is measured in kilograms. Weight is a force (also known as the force of gravity) and is a vector quantity determined by the product of an object's mass and an acceleration due to gravity.
100
Describe if waves transfer energy, matter, or both?
All waves transfer energy, only.
100
How much total charge do three protons carry?
4.8 x 10-19 Coulombs
(e = 1.6 x 10-19 C)
200
A dog walks 5 meters east, then 12 meters north. What is its total distance travelled?
17 meters
(Distance is a scalar measurement; direction is irrelevant.)
200
This graph shows the motion of an object. Determine the object's speed between 2 and 5 seconds.
v = (df-di)/(tf-ti)
v = (40m - 10m) / (5s - 2s) = 10 m/s
200
Imagine a book at rest on a level tabletop. Describe the reaction force to its weight.
The reaction to the book's weight (gravity force) is the gravity force it places on the Earth.
200
A radio wave has a wavelength of 3 meters. What is its velocity?
3 x 108 m/s
All electromagnetic waves travel at the speed of light (c).
200
What does the slope of this graph measure?
A constant between the ratio of voltage and current.
V / I = R
The constant is called Resistance
300
What are the units of the Universal Gravitational constant G?
Nm2/kg2
300
Describe in detail how the range (dx) of a projectile changes as its launch angle increases from 0o through 90o.
A projectile's range will increase as its launch angle increases from 0o up to 45o. At angles greater than 45o the range begins to decrease again, and becomes 0m at 90o.
300
A 20 N box is at rest on a ramp inclined at 250 with the horizontal. Determine the normal force acting on this box.
On inclines, FN = Fgy = Fgcos(o)
We already have Fg = 20 N
FN = (20N)cos(25o) = 18.13 N
300
Imagine two students making transverse waves through a long spring (or Slinky) between themselves. Describe how they could make these waves increase their velocity.
The medium (spring) must be changed if the velocity of a wave is to be changed. The students must increase the tension of the spring (by moving farther apart) to increase the velocity of the waves.
300
Describe why it is safe to be inside a car if it were struck by lightning.
The car acts as a Faraday cage; the electricity will flow around the outside of the car into the ground (even through the tires), but not through the interior of the car.
400
Name any four scalar quantities.
Mass, distance, speed, time, energy, charge (there are others, too)
400
A rocket can accelerate from rest to a velocity of 10 m/s in 0.5 seconds. Assuming its acceleration remains constant, how far will this rocket travel if it flies for 3 seconds?
a = (vf-vi)/t = (10-0)/0.5 = 20 m/s2
d = vit + 1/2at2 = 0 + 1/2(20)(3)2 = 90 meters
400
A 3 kg copper block is accelerating across a level steel table at 2 m/s2. Determine the applied force acting on it.
Fnet = ma = Fapp - Ffk
(3kg)(2m/s2) = Fapp - ukFN
6 N = Fapp - (0.36)(3kg)(9.81m/s2)
6 N = Fapp - (0.36)(3kg)(9.81m/s2)
6 N = Fapp - 10.6 N
Fapp = 16.6 N
400
Describe how the relative motion of air compares to the propagation of a sound wave moving through it.
As a longitudinal wave, sound will cause its medium to vibrate in the parallel direction of its propagation.
400
Describe qualitatively why total resistance of a parallel circuit decreases when resistors are added in parallel (like when you plug a second device into a wall outlet).
By adding a parallel section to a circuit an additional pathway (loop) around the circuit is created. This reduced the overall resistance to the electrons flowing (current) around in a circuit loop.
500
A dog walks 3 m east and 4 m north. What is the angle of its resultant displacement (relative to the horizontal)?
Tan-1(4/3) = 53.13o
500
This graph shows the velocity of an object over time. Solve for the total displacement of the object for the first 9 seconds of its motion.
Displacement from a velocity graph --> Area calculation
Triangle (from 0s-4s): 1/2(4s)(12m) = 24m
Rectangle (from 4s-9s): (5s)(12m) = 60m
Total displacement = 24m + 60m = 84 meters
500
A 2000kg car is attempting a turn of radius 15m on a level road. Its tires are made of rubber and the road is made of dry asphalt. Determine the maximum speed it can successfully make this turn without slipping.
To keep in the turn Fc = Ffs
mv2 / r = uFN --> v2 = uFNr / m
v2 = (0.85)(2000kg)(9.81m/s2)(15m) / (2000kg)
v2 = 125.0775 m2/s2
v = 11.184 m/s500
A ray of light in air enters a piece of unknown glass at an angle of 40o (with the normal). It is observed to transmit into the glass at an angle of 22o. Solve for the index of refraction of this glass, and then solve for the apparent velocity of light through this glass.
Snell's Law: n1sino1 = n2sino2
(1)sin(40o) = n2sin(22o)
n2 = 1.716
n = c/v
1.716 = (3x108 m/s) / v
v = 1.748 x 108 m/s
500
A circuit consisting of of three 10-ohm resistors are set in parallel with a 9V battery. Determine the total current flowing from the battery.
Each resistor uses 9V, so the current through each resistor is I = V/R = 9V/10ohm = 0.9 A
Current adds in parallel, so the total I = 2.7 A total
Or solve for total R = (1/R1 + 1/R2 + 1/R3)-1
so (1/10 + 1/10 + 1/10)-1 = 3.3333 ohms
I = V/R = 9V / 3.3333ohms = 2.7 A total