Let the rain fall down
If we have a circular container whose mass is kg and its volume is 0.75 cubic meters. What is its density?
1kg/m3
Imagine a spaceship passing in front of you at a relative velocity v=0.80c. A member of the crew measures the length of the spaceship, obtaining 0.5 km.
Find the length that is measured by observers located on the Earth.
300 m
Suppose that you observe a spaceship passing in front of you at a relative velocity v=0.75c. According to a clock on Earth, 2.5 seconds passed in the spaceship clock.
Find the time elapsed for an observer inside the spaceship.
1.65s
Find the energy of an object whose mass is 60 kg when standing still.
Speed light 3x108m/s
5.4x1018J
Identify a “conductor” and some examples.
Materials where electric charges are easily transferred, like silver and copper.
What is the fundamental frequency of a sound wave traveling in a tube with a length of 38 cm?
In a closed tube (f1) in an open Tube (f2)
The speed of sound is = 343 m/s.
f1= 225.66 Hz
f2= 4521.32 Hz
A conducting wire forms a 60° angle with respect to a magnetic field B=0.5 T. If the wire length is 50 cm and a 2.0 Amperes current flows through the wire.
Find the resulting force over the wire.
F= 0.433 N
What is the usefulness of Coulomb’s Law?
To calculate the force exercised between two punctual charges.
Describe the different types of electric currents.
Alternating Current: Is the electric current in which both, magnitude and direction, vary cyclically.
Direct Current: Is the current in which electric charge or electrons flow always to the same direction in a closed circuit.
One industrial mill wheel rotates once every 0.2 seconds. What is the angular speed in revolutions per minute?
300 rpm
Describe Kirchhoff’s laws.
Kirchhoff’s current law: The sum of the currents flowing into the node is equal to the sum of the currents flowing out of the node.
Kirchhoff’s voltage law: The sum of the emf around any current closed path is equal to the sum of all IR (voltage) drop around the same close path.
This is an example that shows the Doppler effect.
If you get closer to the sound of an alarm, it is sharper because the waves coming from the alarm are closer to you.
Find the electric potential in a point located at 0.40 meters from a charge.
2.02x105V
What is the frequency heard by a motionless person if an automobile is moving towards the listener at a speed of 120 km/hr, sounding the horn in a 1500 Hz frequency?
Speed of sound = 343 m/s
1,661.28 Hz
Find the electric power that can be generated with 35 Volts and a resistance of 12 Ω.
102.08 A
A copper wire with a length of 50 cm conducts a current of 1.5 A perpendicular to a magnetic field of 0.5 T. What is the magnetic force acting on the wire?
0.375 N
Calculate the magnetic field B in the air at a distance of 5 cm from a long wire, if a current of 20 Amp is flowing through it.
Magnetic permeability at vacuum:
miu= 4pix10-7 Tm/A
8x10-5T
A charge of 1.1x10-19 Ctravels 0.5 meters from point A to point B in a straight path. The potential energy at point B is U=1.8x10-12 J.
Calculate the electric potential of the charge in point B.
16.36X106 Volts
If there are ewo charges, q1= 4µC and q2 = -7 µC, which are 0.076 m apart from each other, what is the magnitude of the force between them?
Do they attract or repel each other?
K=9x109Nm2/C2
43.62 N
There are two great size parallel metallic plates, with equal magnitude but opposite charges. Plates are located at a distance d = 2 cm apart from each other, and the potential difference between them is V=120 Volts.
If the magnetic field is uniform between the plates. What is the magnitude (E) of the electric field?
E=6,000 V/m
A solenoid is made of 200 turns of wire wrapped around an iron nucleus that has a length of 20 cm. If the relative permeability of iron is
Find the current I, required to produce a magnetic induction of 2 T at the interior of the solenoid.
Consider the magnetic permeability at vacuum:
miu=4pix10-7 Tm/A
I=0.122A
Find the magnitude of the electric field in a point on a plate with an even charge of 34 C/m2
Permittivity Constant E0=8.854x10-12C/Nm2
1.92x1012
A plate with an area A= 0.07 m2. An electric field E=80 N/C flows through the plate. The angle between the electric field and the surface of the plate is θ=50°.
Find the magnitude of the electric flow.
3.60 Nm2C
An electric charge q=2x10-16C is immersed in an electric field, whose magnitude E=1.5x10-2 N/C. Find the potential energy in a point located at 60 cm from a plate.
Find the magnitude of the electric flow.
1.8x10-18J
There are two containers with the same capacity, one of them holds 1.92 kg of water while the other holds 3.5 kg of motor oil. Which of the two liquids has a higher density?
Oil is denser than wáter