Physics.docx

Bulacan State University College of Engineering COE FRESHMEN REVIEW SESSIONS

8. The system as shown is in equilibrium. Determine the force exerted by cable AB.

PHYSICS 1 1. Determine the values of P and E to maintain the equilibrium of the forces.

2. Determine the resultant force.

3. A box is being pulled by a force 50 lb exerted by the rope inclined 40ᴼ with horizontal. What’s the effective component of the force pulling the box? 4. In the system shown, a 5 kg block rests on a horizontal table top and is attached with horizontal string to a second string as shown. What is the maximum value for the mass M, if the block is to remain stationary? Assume µs = 0.5

5. A 250 kg weight rests on a 30ᴼ inclined plane. Neglecting friction, how much pull must one exert to bring the weight up the plane? 6. A 56 lb mass rests on horizontal surface. The force needed to move it along the surface is 25 lb . Determine the coefficient friction. 7. A homogeneous ladder 18 ft long and weighing 120 lbs rests against a smooth wall. The angle between it and the floor is 70ᴼ. The coefficient of friction between the floor and the ladder is 0.25 . How far up the ladder can a 180 lb man walk before the ladder slips?

9. Two men are just able to lift a 300 kg weight with a crowbar when the fulcrum for the lever is 0.3 m from the weight. The first man exerts his strength at 0.9m while the second is at 1.5 m from the fulcrum respectively. If the men interchanged their positions, they can raise a 340 kg weight. What amount of forces do the men exert? 10. Determine the resultant force:

11. Determine the centroid of the shaded portion.

12. Determine the abscissa of the centroid for the shaded area as shown.

13. What is the magnitude of resultant force?

14. Compute the moment of force about point A. F = 450 lbs , P = 300 lbs

15.An electric post is supported by a guy wire which exerts a pull of 100N on the top of the post. If the angle between the guy wire and the ground is 60ᴼ . Determine the vertical component of the force supporting the pole. 16. A 150 lb cylindrical tank is at rest as shown. Determine force P requires to move the tank up the higher level surface:

20. An automobile starting from rest speed up to 40ft/sec with a constant acceleration of 4ft/𝑠𝑒𝑐 2 runs at this speed for a time and finally comes to rest with a deceleration of 5ft/𝑠𝑒𝑐 2. If the total distance traveled is 1200ft, find the total time required? 21. A ball is dropped from an 80ft high tower and at the same instance a second ball is thrown vertically of 40 feet per second. When and where will the ball pass each other? 22. A stone is dropped down in a well; 5 seconds later the sound of splash is heard. If the velocity of the sound is 350m/sec, what is the depth of the well? 23. A stone thrown vertically upward has a velocity of 48.3fps. One second later, another stone is thrown vertically upward with a velocity of 96.6fps. How far above the ground will the stones be of the same level? 24. A projectile is fired from an angle of 60ᴼ to the horizontal with an initial velocity of 100ft/sec. After hitting the level ground at the base of the hill, it has curve a horizontal distance of 500ft. How high will the hill?

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17. An automobile moving at a constant velocity of 45ft/sec passes a gasoline station. Two seconds later, another automobile leaves the gasoline station and accelerates at a constant rate of 6ft/𝑠𝑒𝑐 2 . How soon will the second automobile overtake the first? 18. Two cars A and B have a velocity of 60mph in the same direction. A is 250 ft behind B giving it to decelerate at a constant rate of 10 ft/𝑠𝑒𝑐 2 . In what time will A overtake B and how far will each have traveled? 19. A truck traveling along a straight road of 20km/hr increase its speed to 120km/hr in 15 sec. If its acceleration is constant, determine the distance traveled.

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PHYSICS II Two equal point charges of +2.1 x 10-6 C are placed 0.4 m apart. What is the magnitude of the force each exerts on the other? Two capacitors C1 and C2 are connected in parallel and their combined capacitance is measured as 9μF. When they are combined in series their capacitance is 2μF. What are the individual capacitances? If the plate separation for a capacitor is 2.0 x 103 m, determine the area of the plates if the capacitance is exactly 1 F. At what separation will two charges, each of magnitude 6.0 μC, exert a force of 1.4 Non each other? It is branch of physics that deals with the study of electricity at rest. a. Electrodynamics b. Electrostatics c. Electricity d. Electronics It is the property which permits a component to accumulate and store electric charge. a. Inductance b. Battery c. Capacitance

d. Resistance 7. What is the charge of an electron? a. 1.6 x 1019 C b. 1.6 x 10-19 C c. 1.6 x 10-27 C d. 1.6 x 10-12 C 8. A battery causes 250 mA to flow when it is applied to a light bulb with a resistance of 50 ohms. How much current would flow if the same source were applied to a 12 ohm resistor? 9. Three resistors of 4 Ω, 6 Ω and 12Ω are connected together in parallel. This parallel arrangement is then connected in series with a 1 Ω and 2 Ω resistors. If a potential difference of 120V is applied across the end of the circuit, what will be the potential drop across the part of the circuit connected in parallel? 10. Find the total resistance of the circuit

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11. Two resistances R1 and R2 give combined resistance of 4.5 ohms when in series and 1 ohm when in parallel. The resistances are? 12. If you wish to increase the amount of current in a resistor from 120 mA to 160 mA by changing the 24 V source, what should the new voltage setting be? For 21-23, refer to the following circuit diagram:

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What is the voltage drop across R3? What is the current at R2? What is the power dissipated at R1? A toaster oven is plugged into an outlet that provides a voltage difference of 120 V. What power does the oven use if the current is 10A? The temperature at which certain materials lose their permanent magnetic properties a. Carie point b. Curie point c. Caring point d. Curing point A nail that touches a magnet will __________ ? a. Melt b. Demagnetized the magnet c. Become polarized d. Generate an electric current What happens if you cut a magnet in half? a. You get two magnets b. You get a separate south pole and a separate north pole c. It becomes demagnetized d. You get monopoles A magnet will strongly attract a. Diamagnetic material b. Ferromagnetic material c. Paramagnetic material d. Geomagnetic material A 10-m long wire carrying 5 A of current is at right angles to a uniform magnetic field of 0.01 T. What is the magnitude of the force on the wire? A 2m long wire weighs 4 g and carries a 10A current. It is constrained to move only vertically above another wire carrying 15A in the opposite direction. At what separation would its weight be supported by magnetic force? Early concepts of magnetism are introduced by a. Amber b. Magnesia c. Gold d. Lodestone The wavelength of a sound wave in a certain material as measured is 18cm. The frequency of

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the wave is 1900 Hz. Compute the speed of sound wave. What is the number of complete waves which pass a given point in a unit time? a. Amplitude b. Period c. Wavelength d. Frequency It is the bending of wave due to the physical makeup of the medium through which the wave passes. a. Absorption b. Reflection c. Refraction d. Diffraction It is the maximum frequency which the human ear can hear. a. 10,000 Hz b. 20,000 Hz c. 30,000 Hz d. 40,000 Hz It is the ratio of the speed of light in air to the speed of light in the substance. a. Index of reflection b. Index of refraction c. Index of reciprocity d. Index of reference What is the time required for the passing of one complete wave? a. Period b. Frequency c. Amplitude d. Wavelength Ampere-second could be the unit of? a. Current b. Power c. Voltage d. Charge Ohm’s law is not applicable to a. DC Circuits b. High Currents c. Small Resistors d. Semi-conductors