A worker pushed a 34.0 kg block 8.30 m along a level floor at constant speed with a force directed 21.0∘ below the horizontal. If the coefficient of kinetic friction between block and floor was 0.410, what were (a) the work done by the worker's force and (b) the increase in thermal energy of the block-floor system? (a) Number Units (b) Number Units
In a Young's double-slit experiment the wavelength of light used is 484 nm (in vacuum), and the separation between the slits is 1.4×10−6 m. Determine the angle that locates (a) the dark fringe for which m = 0, (b) the bright fringe for which m = 1, (c) the dark fringe for which m = 1, and (d) the bright fringe for which m = 2. (a) Number Units (b) Number Units (c) Number Units (d) Number Units
Juggles the clown stands on one end of a teeter-totter at rest on the ground. Bangles the clown jumps off a platform 2.6 m above the ground and lands on the other end of the teeter-totter, launching Juggles into the air. Juggles rises to a height of 3.9 m above the ground, at which point he has the same amount of gravitational potential energy as Bangles had before he jumped, assuming both potential energies are measured using the ground as the reference level. Bangles' mass is 97 kg. What is Juggles' mass? Number Units
As shown below, on Titan a beam of length L is leaning against a frictionless wall and is in static equilibrium. The center of mass of the beam is located 0.9 L from the lower end of the beam and the beam is exerting a force of 46 N on the wall. Determine the mass of the beam and the minimum coefficient of static friction between the floor and the beam. mass of the beam = μs, min =
A uniformly charged rod of length L and total charge Q lies along the x axis as shown in in the figure below. (Use the following as necessary: Q, L, d, and ke.) (a) Find the components of the electric field at the point P on the y axis a distance d from the origin. Ex = Ey = (b) What are the approximate values of the field components when d > > L? Ex ≈ Ey ≈ Explain why you would expect these results.
A uniformly charged disk with radius R = 30.0 cm and uniform charge density σ = 6.10×10−3 C/m2 lies in the xy-plane, with its center at the origin. What is the electric field (in MN/C) due to the charged disk at the following locations? (a) z = 5.00 cm MN/C (b) z = 10.0 cm MN/C (c) z = 50.0 cm MN/C (d) z = 200 cm MN/C
As shown, the coefficient of kinetic friction between the surface and the larger block is 0.210, and the coefficient of kinetic friction between the surface and the smaller block is 0.320. If F = 11.5 N and M = 0.600 kg, a) what is the acceleration of the masses? a = m/s2 b) what is the tension in the connecting string? T = N
In the figure, a 4.0−kg ball is on the end of a 1.6 m rope that is fixed at 0. The ball is held at point A, with the rope horizontal, and is given an initial downward velocity. The ball moves through three-quarters of a circle with no friction and arrives at B, with the rope tension = 79.8 N. The initial velocity of the ball in m/s, at point A, is closest to
A block of mass m = 3 kg starting at rest accelerates down an inclined plane of angle θ = 35∘. The coefficient of kinetic friction (μk) between the plane and the block is 0.4. After the block accelerates down the plane for 2 second, moving a total distance D down the surface of the plane, what is the magnitude of the work that kinetic friction has done on the block? 56.5 J 62.9 J 0 J 46.2 J 18.7 J
A person with mass m1 = 55.0 kg stands at the left end of a uniform beam with mass m2 = 91.0 kg and a length L = 2.50 m. Another person with mass m3 = 67.0 kg stands on the far right end of the beam and holds a medicine ball with mass m4 = 9.00 kg. Assume that the medicine ball is at the far right end of the beam as well. Let the origin x = 0 of the coordinate system be the left end of the original position of the beam, as shown in the figure. What is the location XCM of the center of mass of the system? XCM =
A block with mass M = 5 kg rests on a surface with a coefficient of static friction of μs = 0.5 and a coefficient of kinetic friction of μk = 0.3. A force is applied pushing it to the right. (a) What is the max force that can be applied to have the block remain stationary? (b) What happens if half the max force, from (a), is applied to the block? (c) The block is traveling to the right with a magnitude of the applied force, |F→A| = 20 N, what is the acceleration of the block?
A loaded ore car has a mass of 950 kg and rolls on rails with negligible friction. It starts from rest and is pulled up a mine shaft by a cable connected to a winch. The shaft is inclined at 35.5∘ above the horizontal. The car accelerates uniformly to a speed of 2.25 m/s in 11.5 s and then continues at constant speed. (a) What power must the winch motor provide when the car is moving at constant speed? kW (b) What maximum power must the motor provide? kW (c) What total energy transfers out of the motor by work by the time the car moves off the end of the track, which is of length 1,250 m? J
A 2.00−nF capacitor with an initial charge of 5.69 μC is discharged through a 2.63−kΩ resistor. (a) Calculate the current in the resistor 9.00 μs after the resistor is connected across the terminals of the capacitor. (Let the positive direction of the current be define such that dQ/dt > 0. ) mA (b) What charge remains on the capacitor after 8.00 μs? μC (c) What is the (magnitude of the) maximum current in the resistor? A
In the figure the battery has potential difference V = 11.5 V, C2 = 3.10 μF, C4 = 4.60 μF, and all the capacitors are initially uncharged. When switch S is closed, a total charge of 10.0 μC passes through point a and a total charge of 7.00 μC passes through point b. What are (a) C1 and (b) C3?
In Figure P 28.67, suppose the switch has been closed for a length of time sufficiently long for the capacitor to become fully charged. (E = 8.70 V, r1 = 11 kΩ, and r2 = 16 kΩ.) Figure P28.67 (a) Find the steady-state current in each resistor. I1 = μA I2 = μA I3−kΩ = μA (b) Find the charge Q on the capacitor. μC (c) The switch is opened at t = 0. Write an equation for the current IR2 in R2 as a function of time. (271 μA)e−t/(0.190 s) (322 μA)e−t/(0.190 s) (322 μA)et/(0.190 s) (271 μA)et/(0.190 s) (d) Find the time that it takes for the charge on the capacitor to fall to one-fifth its initial value. ms