Physics Rotational Mechanics Level: High School
A woman who weighs 4.92 x 10^2 N is leaning against a smooth vertical wall , as the drawing shows at “click here” .a) Find the force FN (directed perpendicular to the wall) exerted on her shoulder by the wall .
b) Find the horizontal component of the force exerted on her shoes by the ground .
c) Find the vertical component of the force exerted on her shoes by the ground .
Physics Rotational Mechanics Level: High School
By means of a rope whose is mass is negligible , two blocks are suspended over a pulley , as the drawing at “click here” shows, with m1 = 11.7 kg and m2 = 45.3 kg . The pulley can be treated as a uniform, solid , cylindrical disk . The downward acceleration of the 45.3 kg block to be exactly one-half the acceleration due to gravity . Noting that the tension in the rope is not the same on each side of the pulley, find the mass of the pulley .
Physics Rotational Mechanics Level: High School
A solid circular disk has a mass of 1.2 kg and a radius of 0.17 m . Each of three identical thin rods has a mass of 0.16 kg . The rods are attached perpendicularly to the plane of the disk at its outer edge to form a three-legged stool . (see the drawing at “click here”) . Find the moment of inertia of the stool with respect to an axis that is perpendicular to the plane of the disk at its center . (Hint: When considering the moment of inertia of each rod , note that all of the mass of each rod is located at the same perpendicular distance from the axis .)
Physics Rotational Mechanics Level: High School
A solid circular disk has a mass of 1.2 kg and a radius of 0.17 m . Each of three identical thin rods has a mass of 0.16 kg . The rods are attached perpendicularly to the plane of the disk at its outer edge to form a three-legged stool . (see the drawing at “click here”) . Find the moment of inertia of the stool with respect to an axis that is perpendicular to the plane of the disk at its center . (Hint: When considering the moment of inertia of each rod , note that all of the mass of each rod is located at the same perpendicular distance from the axis .)
Physics Rotational Mechanics Level: High School
A rotational axis is directed perpendicular to the plane of a square and is located as shown in the drawing figure at “click here” . Two forces F1 and F2 , are applied to diagonally opposite corners , and act along the sides of the square , first shown in part a and then part b of the drawing . In each case the net torque produced by the forces is zero . The square is one meter on a side ,and the magnitude of F2 is 2 times that of F1 , find the distance a and b that locate the axis . Note that a and b are drawn to scale .
Physics Rotational Mechanics Level: High School
The crane shown in the drawing at “click here” is lifting a 180 kg crate upward with an acceleration of 1.5 m/s^2 . The cable from the crate passes over a solid cylindrical pulley at the top of the boom . The pulley has a mass of 130 kg . The cable is then wound onto a hollow cylindrical drum that is mounted on the deck of the crane . The mass of the drum is 150 kg, and its radius is 0.76 m . The engine applies a counterclockwise torque to the drum in order to wind up the cable . What is the magnitude of this torque ? Ignore the mass of the cable .
Physics Waves And Oscillations Level: High School
A light string with a mass per unit length of 9.00 g/m has its end tied to two walls separated by a distance equal to three-fourths the length of the string(see the figure at “click here” . An object of mass m is suspended from the center of the string, putting a tension in the string .a) Find the expression for the transverse wave speed in the string as a function of the mass of the hanging object . (Answer interns of the mass m . )
Physics Waves And Oscillations Level: High School
A sinusoidal sound wave is described by the following displacement wave function .a) Determine the instantaneous displacement from the equilibrium of the elements of air at the position x =0.0508 m at t = 3.05 ms .
b) Determine the maximum speed of a element’s oscillatory motion. (Note : Use the following values as needed , unless otherwise specified . The equilibrium density of air is p = 1.20 kg /m^3 , the speed of sound in air is v = 343 m/s . Pressure variation delta P are measured relative to atmospheric pressure 1.013 x 10^5 Pa).
Physics Waves And Oscillations Level: High School
A vacuum cleaner produces sound with a measured sound level of 62.0 dB .a) What is the intensity of this sound ?
b) What is the pressure amplitude of the sound ?
Physics Waves And Oscillations Level: High School
A plane can fly at Mach 1.38 , which means the speed of the plane is 1.38 times the speed of sound in air ,What is the angle between the directing of propagation of the shock wave and the direction of the plane’s velocity ?
Physics Kinematics Level: High School
projectile motion
A football player kicks a ball at an angle of 37o from the horizontal with an initial speed of 50 ft/sec , and the ball moves in a vertical plane . Find the elapsed time from kickoff until the ball reaches its highest point . Neglect air friction . What is the highest point reached by the ball in the above question ?
Physics Electrostatics Level: High School
An electric field applies a force of 9.11 x 1016 N to an electron emitted from the cathode of a cathode-ray tube at essentially zero velocity . If the field force is constant , find the time required for the electron to reach the screen 20 cm from the cathode ?
Physics Properties Of Matter Level: High School
Gases
a) An ideal gas occupies a volume of 1.0 cm cubed at 20 degrees C and atmospheric pressure . Determine the number of molecules of gas in the container .
b) If the pressure of the 1 cm cubed volume is reduced to 1.0 X 10 to the -11 pa , while the temperature remains constant , how may moles of gas remain in the container ?
Physics Properties Of Matter Level: High School
Gases
One mole of oxygen gas is at a pressure of 6.00 atm and a temperature of 27 degrees C .(a) If the gas is heated at constant volume until the pressure triples , what is the final temperature ?
(b) If the gas is heated so that both the pressure and volume are doubled , what is the final temperature ?
Physics Current Electricity Level: High School
Heating effect of current
One light bulb is marked “15 W 120 V” and another “60 W 120 V” . This means that each transforms this amount of electrical energy into light and heat per second when plugged into a constant 120-V potential difference . (You may assume 3 significant digits for the markings) .a) Find the resistance of each bulb . When they are connected to a 120 V power supply which bulb is brighter ?
b) How longs does it take for 1.00 C to pass through the dim bulb ? How is this charge different upon its exit versus its entry into the bulb ?
c) How long does it take the dim bulb to dissipate 1.00 J of energy ?
d) Find the cost of running the dim bulb continuously for 30.0 days if the electric company sells its product at $0.800 per kilowatt-hour (kWh) .
e) What physics quantity does the electric company sell ? What is the price for one SI unit of this quantity ?
f) Assume you can buy gasoline at $2.00 gallon and each gallon contains 114000 Btu . What is the ratio of the cost energy from the electrical power company over the cost of energy from the gas pump ?
