Exam 1: A: Foundations

Albert uses as his unit of length (for walking to visit his neighbors or plowing his fields)the albert (A),the distance Albert can throw a small rock. One albert is 92 meters. How many square alberts is equal to one acre? (1 acre = 43,560 ft² = 4050 m²)

The shortest wavelength of visible light is approximately 400 nm. Express this wavelength in centimeters.

If a woman weighs 125 lb,her mass expressed in kilograms is x kg,where x is

Suppose you place your face in front of a concave mirror.Which one of the following statements is correct?

An ideal air-filled parallel-plate capacitor has round plates and carries a fixed amount of equal but opposite charge on its plates.All the geometric parameters of the capacitor (plate diameter and plate separation)are now DOUBLED.If the original capacitance was C₀,what is the new capacitance?

A -3.0-μC point charge and a -9.0-μC point charge are initially extremely far apart.How much work does it take to bring the -3.0-μC charge to x = 3.0 mm,y = 0.00 mm and the -9.0-μC charge to x = -3.0 mm,y = 0.00 mm? (k = 1/4πε₀ = 8.99 × 10⁹ N • m²/C²)

In the figure,the thin lens forms a real image of the object 94.0 cm from the object.What is the focal length of the lens?

A mass is pressed against (but is not attached to)an ideal horizontal spring on a frictionless horizontal surface.After being released from rest,the mass acquires a maximum speed v and a maximum kinetic energy K.If instead the mass initially compresses the spring twice as far:

A potter's wheel,with rotational inertia 46 kg • m²,is spinning freely at 40 rpm.The potter drops a lump of clay onto the wheel,where it sticks a distance 1.2 m from the rotational axis.If the subsequent angular speed of the wheel and clay is 32 rpm what is the mass of the clay?

Three objects are connected as shown in the figure.The strings and frictionless pulleys have negligible masses,and the coefficient of kinetic friction between the 2.0-kg block and the table is 0.25.What is the acceleration of the 2.0-kg block?

The sound level at 1.0 m from a certain talking person talking is 60 dB.You are surrounded by five such people,all 1.0 m from you and all talking equally loud at the same time.The threshold of hearing is 1.0 × 10^-12 W/m².What sound level are you being exposed to? You can neglect any absorption,reflection,or interference of the sound.The threshold of hearing is 1.0 × 10^-12 W/m².

A 4.00-kg block rests between the floor and a 3.00-kg block as shown in the figure. The 3.00-kg block is tied to a wall by a horizontal rope. If the coefficient of static friction is 0.800 between each pair of surfaces in contact,what horizontal force F must be applied to the 4.00-kg block to make it move?

Two spaceships are approaching one another,each at a speed of 0.28c relative to a stationary observer on Earth.What speed does an observer on one spaceship record for the other approaching spaceship?

If two forces of equal magnitude act on an object that is hinged at a pivot,the force acting farther from the pivot must produce the greater torque about the pivot.

Sometimes an experiment requires a certain pure gas to be used at reduced pressure.One way to achieve this is to purchase a sealed glass container filled with the gas,and to introduce the gas into a vacuum by attaching the glass container to the vacuum chamber and breaking the tip of the glass container using a metallic bean and a magnet.If the volume of the glass container is 1.0 L and it is at a pressure of 1.0 × 10⁵ Pa and if the vacuum chamber has a volume of 2.0 L,what will the pressure be after the gas,which is to be assumed to be an ideal gas,is released into the vacuum chamber and the temperature has returned to its original value? (Note that the glass container remains part of the system.)

The long straight wire in the figure carries a current I that is decreasing with time at a constant rate.The circular loops A,B,and C all lie in a plane containing the wire.The induced emf in each of the loops A,B,and C is such that

A heat engine with an efficiency of 30.0% performs 2500 J of work.How much heat is discharged to the lower temperature reservoir?

An LRC ac series circuit with R = 15 Ω,L = 25 mH,and C = 30 μF,is attached to a 100-V (rms)ac power supply.The frequency of the power supply is adjusted so that the circuit is in resonance. (a)What is the rms current in the circuit? (b)What is the power dissipated by the circuit?

On the earth,when an astronaut throws a 0.250-kg stone vertically upward,it returns to his hand a time T later.On planet X he finds that,under the same circumstances,the stone returns to his hand in 2T.In both cases,he throws the stone with the same initial velocity and it feels negligible air resistance.The acceleration due to gravity on planet X (in terms of g)is

A 200 g hockey puck is launched up a metal ramp that is inclined at a 30° angle.The coefficients of static and kinetic friction between the hockey puck and the metal ramp are μ_s = 0.40 and μ_k = 0.30,respectively.The puck's initial speed is 63 m/s. What vertical height does the puck reach above its starting point?