FREE Trial S
study help categories /Physics

Top Selling Physics Questions

Two particles collide and bounce apart. FIGURE EX11.31 shows the initial momenta of both and the final momentum of particle 2. What is the final momentum of particle 1? Write your answer using unit... An object at rest explodes into three fragments. FIGURE EX11.32 shows the momentum vectors of two of the fragments. What is the momentum of the third fragment? Write your answer using unit vectors.... A 20 g ball of clay traveling east at 3.0 m/s collides with a 30 g ball of clay traveling north at 2.0 m/s. What are the speed and the direction of the resulting 50 g ball of clay? Give your answer... At the center of a 50-m-diameter circular ice rink, a 75 kg skater traveling north at 2.5 m/s collides with and holds on to a 60 kg skater who had been heading west at 3.5 m/s. a. How long will it... A small rocket with 15 kN thrust burns 250 kg of fuel in 30 s. What is the exhaust speed of the hot gases? A 2.0 kg object is moving to the right with a speed of 1.0 m/s when it experiences the force shown in FIGURE EX11.8. What are the objects speed and direction after the force ends? F, (N) 1.0 s - t... A 250 g ball collides with a wall. FIGURE EX11.13 shows the balls velocity and the force exerted on the ball by the wall. What is v fx , the balls rebound velocity? F, (N) V, (m/s) 500 - VEr 8.0 ms... A rocket in deep space has an exhaust-gas speed of 2000 m/s. When the rocket is fully loaded, the mass of the fuel is five times the mass of the empty rocket. What is the rockets speed when half the... A tennis player swings her 1000 g racket with a speed of 10 m/s. She hits a 60 g tennis ball that was approaching her at a speed of 20 m/s. The ball rebounds at 40 m/s. a. How fast is her racket... A 60 g tennis ball with an initial speed of 32 m/s hits a wall and rebounds with the same speed. FIGURE P11.39 shows the force of the wall on the ball during the collision. What is the value of F max... A 500 g cart is released from rest 1.00 m from the bottom of a frictionless, 30.0° ramp. The cart rolls down the ramp and bounces off a rubber block at the bottom. FIGURE P11.40 shows the force... A particle of mass m is at rest at t = 0. Its momentum for t > 0 is given by p x = 6t 2 kg m/s, where t is in s. Find an expression for F x (t), the force exerted on the particle as a function of... A rocket in deep space has an empty mass of 150 kg and exhausts the hot gases of burned fuel at 2500 m/s. It is loaded with 600 kg of fuel, which it burns in 30 s. What is the rockets speed 10 s, 20... A spaceship of mass 2.0 10 6 kg is cruising at a speed of 5.0 10 6 m/s when the antimatter reactor fails, blowing the ship into three pieces. One section, having a mass of 5.0 10 5 kg, is blown... Is the center of mass of the dumbbell in FIGURE Q12.1 at point a, b, or c? Explain. a b FIGURE Q12.1 A high-speed drill reaches 2000 rpm in 0.50 s. a. What is the drills angular acceleration? b. Through how many revolutions does it turn during this first 0.50 s? A ceiling fan with 80-cm-diameter blades is turning at 60 rpm. Suppose the fan coasts to a stop 25 s after being turned off. a. What is the speed of the tip of a blade 10 s after the fan is turned... An 18-cm-long bicycle crank arm, with a pedal at one end, is attached to a 20-cm-diameter sprocket, the toothed disk around which the chain moves. A cyclist riding this bike increases her pedaling... You have two solid steel spheres. Sphere 2 has twice the radius of sphere 1. By what factor does the moment of inertia I 2 of sphere 2 exceed the moment of inertia I 1 of sphere 1? The three masses shown in Figure EX12.7 are connected by massless, rigid rods. What are the coordinates of the center of mass? B 300 g 10 cm 12 cm 100 g 200 g FIGURE EX12.7 Six forces are applied to the door in FIGURE Q12.8. Rank in order, from largest to smallest, the six torques Ï a to Ï f about the hinge on the left. Explain. F LI4 L/4 L/4 L/4 ' Td 2F T. ... What is the rotational kinetic energy of the earth? Assume the earth is a uniform sphere. Data for the earth can be found inside the back cover of the book. The three 200 g masses in Figure EX12.11 are connected by massless, rigid rods. a. What is the triangles moment of inertia about the axis through the center? b. What is the triangles kinetic energy... The solid cylinder and cylindrical shell in FIGURE Q12.11 have the same mass, same radius, and turn on frictionless, horizontal axles. (The cylindrical shell has lightweight spokes connecting the... The four masses shown in Figure EX12.13 are connected by massless, rigid rods. a. Find the coordinates of the center of mass. b. Find the moment of inertia about an axis that passes through mass A... Is the angular momentum of disk a in FIGURE Q12.13 larger than, smaller than, or equal to the angular momentum of disk b? Explain. Ib = 2r, wn = 2w, b FIGURE Q12.13 In Figure EX12.18, what is the net torque about the axle? 30 N 4.0 cm 20 N The three masses shown in Figure EX12.15 are connected by massless, rigid rods. a. Find the coordinates of the center of mass. b. Find the moment of inertia about an axis that passes through mass A... In Figure EX12.19, what magnitude force provides 5.0 N m net torque about the axle? 10 cm 10 cm The 20-cm-diameter disk in Figure EX12.20 can rotate on an axle through its center. What is the net torque about the axle? y 30 N, 30 N 45 5.0 5.0 c cm 20 N 20 N FIGURE EX12.20 An objects moment of inertia is 2.0 kg m 2 . Its angular velocity is increasing at the rate of 4.0 rad/s per second. What is the net torque on the object? An object whose moment of inertia is 4.0 kg m 2 experiences the torque shown in Figure EX12.25. What is the objects angular velocity at t = 3.0 s? Assume it starts from rest. (Nm) 0+ -t (s) 3 FIGURE... A 1.0 kg ball and a 2.0 kg ball are connected by a 1.0-m-long rigid, massless rod. The rod is rotating cw about its center of mass at 20 rpm. What net torque will bring the balls to a halt in 5.0 s? Starting from rest, a 12-cm-diameter compact disk takes 3.0 s to reach its operating angular velocity of 2000 rpm. Assume that the angular acceleration is constant. The disks moment of inertia is 2.5... A 4.0 kg, 36-cm-diameter metal disk, initially at rest, can rotate on an axle along its axis. A steady 5.0 N tangential force is applied to the edge of the disk. What is the disks angular velocity,... The object shown in Figure EX12.30 is in equilibrium. What are the magnitudes of F 1 and F 2 ? 2.0 m 1.0 m f40 N Massless FIGURE EX12.30 The 3.0-m-long, 100 kg rigid beam of Figure EX12.31 is supported at each end. An 80 kg student stands 2.0 m from support 1. How much upward force does each support exert on the beam? 2.0 m 3.0 m... A solid sphere of radius R is placed at a height of 30 cm on a 15 slope. It is released and rolls, without slipping, to the bottom. From what height should a circular hoop of radius R be released on... Evaluate the cross products A Ã B and C Ã D. (a) A (b) 4 90 45 FIGURE EX12.38 Vector A = 3i + j and vector B = 3i - 2j + 2k. What is the cross product A B? Force F = -10j N is exerted on a particle at r = (5i + 5j) m. What is the torque on the particle about the origin? A 1.3 kg ball on the end of a lightweight rod is located at (x, y) = (3.0 m, 2.0 m), where the y-axis is vertical. The other end of the rod is attached to a pivot at (x, y) = (0 m, 3.0 m). What is... What are the magnitude and direction of the angular momentum relative to the origin of the 200 g particle in FIGURE EX12.42? 200 g 45 2.0 m- 3.0 m/s - 1.0 m What is the angular momentum vector of the 2.0 kg, 4.0-cm-diameter rotating disk in FIGURE EX12.43? y 600 rpm FIGURE EX12.43 What is the angular momentum vector of the 500 g rotating bar in FIGURE EX12.44? 120 rpm 2.0 m FIGURE EX12.44 How fast, in rpm, would a 5.0 kg, 22-cm-diameter bowling ball have to spin to have an angular momentum of 0.23 kg m 2 /s? A 2.0 kg, 20-cm-diameter turntable rotates at 100 rpm on frictionless bearings. Two 500 g blocks fall from above, hit the turntable simultaneously at opposite ends of a diameter, and stick. What is... A 75 g, 6.0-cm-diameter solid spherical top is spun at 1200 rpm on an axle that extends 1.0 cm past the edge of the sphere. The tip of the axle is placed on a support. What is the tops precession... A 300 g ball and a 600 g ball are connected by a 40-cm-long massless, rigid rod. The structure rotates about its center of mass at 100 rpm. What is its rotational kinetic energy? An 800 g steel plate has the shape of the isosceles triangle shown in FIGURE P12.50. What are the x- and y-coordinates of the center of mass? y 20 cm 30 cm FIGURE P12.50 Determine the moment of inertia about the axis of the object shown in FIGURE P12.51. Rod of p , mass M Rotation axis FIGURE P12.51 What is the moment of inertia of a 2.0 kg, 20-cm-diameter disk for rotation about an axis (a) Through the center, (b) Through the edge of the disk? Calculate the moment of inertia of the rectangular plate in FIGURE P12.54 for rotation about a perpendicular axis through the center. Rotation axis L L FIGURE P12.54 a. A disk of mass M and radius R has a hole of radius r centered on the axis. Calculate the moment of inertia of the disk. b. Confirm that your answer agrees with Table 12.2 when r = 0 and when r =... Consider a solid cone of radius R, height H, and mass M. The volume of a cone is 1/3HR 2 . a. What is the distance from the apex (the point) to the center of mass? b. What is the moment of inertia... A persons center of mass is easily found by having the person lie on a reaction board. A horizontal, 2.5-m-long, 6.1 kg reaction board is supported only at the ends, with one end resting on a scale... A 40 kg, 5.0-m-long beam is supported by, but not attached to, the two posts in Figure P12.60. A 20 kg boy starts walking along the beam. How close can he get to the right end of the beam without it... Rank in order, from largest to smallest, the angular accelerations a to d in FIGURE Q12.10. Explain. 2F 2F 2m 2r 2r 2m b d FIGURE Q12.10 A 120-cm-wide sign hangs from a 5.0 kg, 200-cm-long pole. A cable of negligible mass supports the end of the rod as shown in Figure P12.62. What is the maximum mass of the sign if the maximum tension... A piece of modern sculpture consists of an 8.0-m-long, 150 kg stainless steel bar passing diametrically through a 50 kg copper sphere. The center of the sphere is 2.0 m from one end of the bar. To be... The 2.0 kg, 30-cm-diameter disk in Figure P12.66 is spinning at 300 rpm. How much friction force must the brake apply to the rim to bring the disk to a halt in 3.0 s? Brake FIGURE P12.66 A 30-cm-diameter, 1.2 kg solid turntable rotates on a 1.2-cm diameter, 450 g shaft at a constant 33 rpm. When you hit the stop switch, a brake pad presses against the shaft and brings the turntable... A hollow sphere is rolling along a horizontal floor at 5.0 m/s when it comes to a 30 incline. How far up the incline does it roll before reversing direction? Flywheels are large, massive wheels used to store energy. They can be spun up slowly, then the wheels energy can be released quickly to accomplish a task that demands high power. An industrial... Your engineering team has been assigned the task of measuring the properties of a new jet-engine turbine. Youve previously determined that the turbines moment of inertia is 2.6 kg m 2 . The next job... A cylinder of radius R, length L, and mass M is released from rest on a slope inclined at angle . It is oriented to roll straight down the slope. If the slope were frictionless, the cylinder would... A long, thin rod of mass M and length L is standing straight up on a table. Its lower end rotates on a frictionless pivot. A very slight push causes the rod to fall over. As it hits the table, what... The marble rolls down the track shown in FIGURE P12.75 and around a loop-the-loop of radius R. The marble has mass m and radius r. What minimum height h must the track have for the marble to make it... A satellite follows the elliptical orbit shown in FIGURE P12.77. The only force on the satellite is the gravitational attraction of the planet. The satellites speed at point a is 8000 m/s. a. Does... A merry-go-round is a common piece of playground equipment. A 3.0-m-diameter merry-go-round with a mass of 250 kg is spinning at 20 rpm. John runs tangent to the merry go-round at 5.0 m/s, in the... A 45 kg figure skater is spinning on the toes of her skates at 1.0 rev/s. Her arms are outstretched as far as they will go. In this orientation, the skater can be modeled as a cylindrical torso (40... The two blocks in FIGURE CP12.86 are connected by a massless rope that passes over a pulley. The pulley is 12 cm in diameter and has a mass of 2.0 kg. As the pulley turns, friction at the axle exerts... A rod of length L and mass M has a nonuniform mass distribution. The linear mass density (mass per length) is = cx 2 , where x is measured from the center of the rod and c is a constant. a. What are... In FIGURE CP12.88, a 200 g toy car is placed on a narrow 60-cm-diameter track with wheel grooves that keep the car going in a circle. The 1.0 kg track is free to turn on a frictionless, vertical... Is the earths gravitational force on the sun larger than, smaller than, or equal to the suns gravitational force on the earth? Explain. A 1000 kg satellite and a 2000 kg satellite follow exactly the same orbit around the earth. a. What is the ratio F 1 /F 2 of the gravitational force on the first satellite to that on the second... The International Space Station orbits 300 km above the surface of the earth. What is the gravitational force on a 1.0 kg sphere inside the International Space Station? Two 65 kg astronauts leave earth in a spacecraft, sitting 1.0 m apart. How far are they from the center of the earth when the gravitational force between them is as strong as the gravitational force... Why is the gravitational potential energy of two masses negative? That saying because thats what the equation gives is not an explanation. A 20 kg sphere is at the origin and a 10 kg sphere is at x = 20 cm. At what position on the x-axis could you place a small mass such that the net gravitational force on it due to the spheres is zero? The escape speed from Planet X is 10,000 m/s. Planet Y has the same radius as Planet X but is twice as dense. What is the escape speed from Planet Y? a. What is the free-fall acceleration at the surface of the sun? b. What is the free-fall acceleration toward the sun at the distance of the earth? The mass of Jupiter is 300 times the mass of the earth. Jupiter orbits the sun with T Jupiter = 11.9 yr in an orbit with r Jupiter = 5.2r earth . Suppose the earth could be moved to the distance of... Satellites in near-earth orbit experience a very slight drag due to the extremely thin upper atmosphere. These satellites slowly but surely spiral inward, where they finally burn up as they reach the... A sensitive gravimeter at a mountain observatory finds that the free-fall acceleration is 0.0075 m/s 2 less than that at sea level. What is the observatorys altitude? Saturns moon Titan has a mass of 1.35 10 23 kg and a radius of 2580 km. What is the free-fall acceleration on Titan? A newly discovered planet has a radius twice as large as earths and a mass five times as large. What is the free-fall acceleration on its surface? Suppose we could shrink the earth without changing its mass. At what fraction of its current radius would the free-fall acceleration at the surface be three times its present value? Planet Z is 10,000 km in diameter. The free-fall acceleration on Planet Z is 8.0 m/s 2 . a. What is the mass of Planet Z? b. What is the free-fall acceleration 10,000 km above Planet Zs north pole? An astronaut on earth can throw a ball straight up to a height of 15 m. How high can he throw the ball on Mars? A space station orbits the sun at the same distance as the earth but on the opposite side of the sun. A small probe is fired away from the station. What minimum speed does the probe need to escape... Nothing can escape the event horizon of a black hole, not even light. You can think of the event horizon as being the distance from a black hole at which the escape speed is the speed of light, 3.00 ... You have been visiting a distant planet. Your measurements have determined that the planets mass is twice that of earth but the free-fall acceleration at the surface is only one-fourth as large. a.... Two meteoroids are heading for earth. Their speeds as they cross the moons orbit are 2.0 km/s. a. The first meteoroid is heading straight for earth. What is its speed of impact? b. The second misses... A binary star system has two stars, each with the same mass as our sun, separated by 1.0 10 12 m. A comet is very far away and essentially at rest. Slowly but surely, gravity pulls the comet toward... The asteroid belt circles the sun between the orbits of Mars and Jupiter. One asteroid has a period of 5.0 earth years. What are the asteroids orbital radius and speed? You are the science officer on a visit to a distant solar system. Prior to landing on a planet you measure its diameter to be 1.8 10 7 m and its rotation period to be 22.3 hours. You have previously... Three satellites orbit a planet of radius R, as shown in FIGURE EX13.26. Satellites S 1 and S 3 have mass m. Satellite S 2 has mass 2m. Satellite S 1 orbits in 250 minutes and the force on S 1 is... A satellite orbits the sun with a period of 1.0 day. What is the radius of its orbit? A new planet is discovered orbiting the star Vega in a circular orbit. The planet takes 55 earth years to complete one orbit around the star. Vegas mass is 2.1 times the suns mass. What is the radius...
Showing 3800 - 3900 of 5000