Exam 1: A: Foundations

A 1.2-kg spring-activated toy bomb slides on a smooth surface along the x-axis with a speed of 0.50 m/s.At the origin 0,the bomb explodes into two fragments.Fragment 1 has a mass of 0.40 kg and a speed of 0.90 m/s along the negative y-axis.In the figure,the angle θ,made by the velocity vector of fragment 2 and the x-axis,is closest to

If,in a parallel universe,π has the value 3.14149,express π in that universe to four significant figures.

An astronaut is in equilibrium when he is positioned 140 km from the center of asteroid X and 581 km from the center of asteroid Y,along the straight line joining the centers of the asteroids.What is the ratio of the masses X/Y of the asteroids?

An electric dipole consists of charges ±5.00 µC separated by 1.20 mm.It is placed in a vertical electric field of magnitude 525 N/C oriented as shown in the figure.The magnitude of the net torque this field exerts on the dipole is closest to

The angular acceleration of a wheel is given in rad/s² by 45t³ - 11t⁴, where t is in seconds.If the wheel starts from rest at t = 0.00 s,when is the next time the wheel is at rest?

A large stick is pivoted about one end and allowed to swing back and forth with no friction as a physical pendulum.The mass of the stick is 5.40 kg and its center of gravity (found by finding its balance point)is 1.80 m from the pivot.If the period of the swinging stick is 6.90 seconds,what is the moment of inertia of the stick about an axis through the pivot?

A 1.15-kg grinding wheel 22.0 cm in diameter is spinning counterclockwise at a rate of 20.0 revolutions per second. When the power to the grinder is turned off,the grinding wheel slows with constant angular acceleration and takes 80.0 s to come to a rest. (a)What was the angular acceleration (in rad/s²)of the grinding wheel as it came to rest if we take a counterclockwise rotation as positive? (b)How many revolutions did the wheel make during the time it was coming to rest?

A jet aircraft,in level flight at constant speed,is observed directly overhead.A sonic boom is heard later,at which time the line of sight to the aircraft forms a 56° angle with respect to the horizontal.The speed of sound is 325 m/s.What is the Mach number (the ratio of the speed of the jet to the speed of sound)for the aircraft?

A 10.0-kg shell is traveling horizontally to the right at 25.0 m/s relative to the ground when it explodes into two fragments,one of mass 3.00 kg and the other of mass 7.00 kg.The lighter fragment goes directly forward,and the explosion releases 1.50 × 10³ J of mechanical energy to the fragments.Find the magnitude and direction of the velocity of the heavier fragment relative to the ground just after the explosion.Ignore the effect of any ejected gases.

A brick is resting on a rough incline as shown in the figure.The friction force acting on the brick,along the incline,is

Suppose that an object is moving with constant nonzero acceleration.Which of the following is an accurate statement concerning its motion?

A 72.0-kg person pushes on a small doorknob with a force of 5.00 N perpendicular to the surface of the door. The doorknob is located 0.800 m from axis of the frictionless hinges of the door. The door begins to rotate with an angular acceleration of 2.00 rad/s². What is the moment of inertia of the door about the hinges?

In addition to 1 m = 39.37 in.,the following exact conversion equivalents are given: 1 mile = 5280 ft, 1 ft = 12 in,1 hour = 60 min,and 1 min = 60 s. If a particle has a velocity of 8.4 miles per hour,its velocity,in m/s,is closest to

A person who weighs 550 N empties her lungs as much as possible and is then completely immersed in water (of density 1000 kg/m³)while suspended from a harness.Her apparent weight is now 21.2 N.What is her density?

A wire segment 1.2 m long carries a current I = 3.5 A and is oriented as shown in the figure.A uniform magnetic field of magnitude 0.50 T pointing toward the -x direction is present as shown.The +z-axis points directly into the page.What is the magnetic force vector on the wire segment?

What is the maximum theoretical efficiency possible for a heat engine operating between a reservoir in which ice and water coexist,and a reservoir in which water and steam coexist? The pressure is constant at 1.0 atmosphere for both reservoirs.

The figure shows three identical lightbulbs connected to a battery having a constant voltage across its terminals.What happens to the brightness of lightbulb 1 when the switch S is closed?

If the electric field and magnetic field of an electromagnetic wave are given by E = E₀ sin(kx - ωt)and B = B₀ sin(kx - ωt),and if the value of E₀ is 51 µV/m,what is the value of B₀? (c = 3.0 × 10⁸ m/s)

Two pure tones are sounded together and a particular beat frequency is heard.What happens to the beat frequency if the frequency of one of the tones is increased?

An object is attached to a vertical ideal massless spring and bobs up and down between the two extreme points A and B.When the kinetic energy of the object is a minimum,the object is located