Exam 1: A: Foundations

On a horizontal frictionless floor,a worker of weight 0.900 kN pushes horizontally with a force of 0.200 kN on a box weighing 1.80 kN.As a result of this push,which statement could be true?

In the figure,two parallel wires carry currents of magnitude I in opposite directions.A rectangular loop is midway between the wires.The current I is decreasing with time.The induced current through the resistor R is

The figure shows a 2.0-cm diameter roller that turns at 90 rpm.A 4.0-cm wide plastic film is being wrapped onto the roller,and this plastic carries an excess electric charge having a uniform surface charge density of 5.0 nC/cm².What is the current of the moving film?

Ions having equal charges but masses of M and 2M are accelerated through the same potential difference and then enter a uniform magnetic field perpendicular to their path.If the heavier ions follow a circular arc of radius R,what is the radius of the arc followed by the lighter?

Two bodies P and Q on a smooth horizontal surface are connected by a light cord.The mass of P is greater than that of Q.A horizontal force (of magnitudeF) is applied to Q as shown in the figure, accelerating the bodies to the right. The magnitude of the force exerted by the connecting cord on body P will be

Light is incident normally from air onto a liquid film that is on a glass plate.The liquid film is 164 nm thick,and the liquid has index of refraction 1.60.The glass has index of refraction n = 1.50.Calculate the longest visible wavelength (as measured in air)of the light for which there will be totally destructive interference between the rays reflected from the top and bottom surfaces of the film.(Assume that the visible spectrum lies between 400 and 700 nm.)

An electromagnetic wave has a peak electric field of 3.0 kV/m.What is the intensity of the wave? (c = 3.0 × 10⁸ m/s,μ₀ = 4π × 10^-7 T • m/A,ε₀ = 8.85 × 10^-12 C²/N • m²)

What is the critical angle for light traveling from crown glass (n = 1.52)into water (n = 1.33)?

Two objects are connected by a very light flexible string as shown in the figure,where M = 0.60 kg and m = 0.40 kg. You can ignore friction and the mass of the pulley. (a) Draw free-body diagrams for each object. (b) Calculate the magnitude of the acceleration of each object. (c) Calculate the tension in the string.

A circular cylinder of height 1.20 m having faces of diameter 0.620 m is immersed in water of density 1.00 × 10³ kg/m³ with its axis vertical so that its faces are parallel to the surface of the water.The upper face is 2.50 m below the surface of the water.The net force on this cylinder is observed to be 1120 N downward.Atmospheric pressure is 1.01 × 10⁵ Pa.What is the weight of the cylinder?

The x component of the velocity of an object vibrating along the x-axis obeys the equation v_x(t)= (0.445 m/s)sin[(25.4 rad/s)t + 0.223]. (a)What is the amplitude of the motion of this object? (b)What is the maximum acceleration of the vibrating object?

At what rate would the current in a 100-mH inductor have to change to induce an emf of 1000 V in the inductor?

A crane lifts a 425 kg steel beam vertically a distance of 117 m.How much work does the crane do on the beam if the beam accelerates upward at 1.8 m/s²? Neglect frictional forces.

In an experiment,a student brings up the rotational speed of a piece of laboratory apparatus to 30.0 rpm.She then allows the apparatus to slow down uniformly on its own,and counts 240 revolutions before the apparatus comes to a stop.The moment of inertia of the apparatus is known to be 0.0850 kg•m².What is the magnitude of the retarding torque on the apparatus?

A small glass bead has been charged to 8.0 nC.What is the magnitude of the electric field 2.0 cm from the center of the bead? (k = 1/4πε₀ = 8.99 × 10⁹ N • m²/C²)

A firecracker breaks up into several pieces,one of which has a mass of 200 g and flies off along the X-axis with a speed of 82.0 m/s.A second piece has a mass of 300 g and flies off along the y-axis with a speed of 45.0 m/s.What are the magnitude and direction of the total momentum of these two pieces?

In the figure,an open tank contains a layer of oil floating on top of a layer of water (of density 1000 kg/m³)that is 3.0 m thick,as shown.What must be the thickness of the oil layer if the gauge pressure at the bottom of the tank is to be 5.0 × 10⁴ Pa? The density of the oil is 510 kg/m³.

In the figure,two identical ideal massless springs have unstretched lengths of 0.25 m and spring constants of 700 N/m.The springs are attached to a small cube and stretched to a length L of 0.30 m as in Figure A.An external force P pulls the cube a distance D = 0.020 m to the right and holds it there.(See Figure B.)The external force P,that holds the cube in place in Figure B,is closest to

A plane flies toward a stationary siren at 1/4 the speed of sound.Then the plane stands still on the ground and the siren is driven toward it at 1/4 the speed of sound.In both cases,a person sitting in the plane will hear the same frequency of sound from the siren.

A 110-V hair dryer is rated at 1200 W. What current will it draw when operating from a 110-V electrical outlet?