A 1.3 kg mass is pulled by a constant tension 23.4 N along a rough surface with coefficient of friction 0.3. The mass is then pulled by the same magnitude tension, along the same surface, but the tension is directed at an angle of 28.1 deg above horizontal. What is the ratio of the magnitudes of friction forces between these two scenarios Ffθ/Ffflat ? (please provide your answer to 2 decimal places)
Now consider a much simpler scenario in which the magnetic field B→ and the velocity v→ of the metal bar are both constant, and the metal rails have been replaced by nonconducting wooden rails (which introduces a significant amount of friction, overcome by the external pulling force). (i) [3 pts] What is the magnetic force (direction and magnitude) on the metal bar in this scenario? (ii) [5 pts] What is the magnetic force (direction and magnitude) on an electron in the metal bar in this scenario? (iii) [5 pts] What is the electric field (direction and magnitude) in the metal bar in this scenario?
A bullet with a mass mb = 11.5 g is fired into a block of wood at velocity vb = 245 m/s. The block is attached to a spring that has a spring constant k of 205 N/m. The block and bullet continue to move, compressing the spring by 35.0 cm before the whole system momentarily comes to a stop. Assuming that the surface on which the block is resting is frictionless, determine the mass mw of the wooden block. mw = kg
A projectile is fired at v0 = 394.0 m/s at an angle of θ = 68.1∘, with respect to the horizontal. Assume that air friction will shorten the range by 33.1%. How far will the projectile travel in the horizontal direction, R ? distance traveled: m
At time t in hours, 0 ≤ t ≤ 1, a 3.7 kg log is burning on a camp fire at rate of 8ln(1 + t) kg per hour. (a) How much of the log is burned between t = 0 and t = 1? Round answer to three decimal places. Total quantity burned between t = 0 and t = 1: i kg . (b) If none of the log has been burned at t = 0, how much remains at t = 1 ? Round answer to three decimal places. Total that remains at t = 1: kg.
A box of mass M is pushed a distance Δx across a level floor by a constant applied force F. The coefficient of kinetic friction between the box and the floor is μ. Assuming the box starts from rest, derive an expression for the final velocity vf of the box. vf = Enter your expression in terms of given quantities, the gravitational acceleration g, and integer coefficients.
In the overhead view of Figure, a 300 g ball with a speed v of 6.0 m/s strikes a wall at angle θ of 30∘ and then rebounds with the same speed and angle. It is in contact with the wall for 10 ms. In unit vector notation, what are (a) The impulse on the ball from the wall and (b) The average force on the wall from the ball
A man shines a flashlight from a boat into the water, illuminating a rock as in the figure below. What is the angle of incidence θ1 (in degrees)?
What is the magnitude of the relativistic momentum of a proton with a relativistic total energy of 3.4×10−10 J? Number Units
Location A is 2.50 m to the right of a point charge q. Location B lies on the same line and is 4.00 m to the right of the charge. The potential difference VB−VA = 47.0 V. What is the magnitude and sign of the charge? Number Units
A particle known as a pion lives for a short time before breaking apart into other particles. Suppose a pion is moving at a speed of 0.987c, and an observer who is stationary in a laboratory measures the pion's lifetime to be 3.4×10−8 s. (a) What is the lifetime according to a hypothetical person who is riding along with the pion? (b) According to this hypothetical person, how far does the laboratory move before the pion breaks apart? (a) Number Units (b) Number Units
What resistance R should be connected in series with an inductance L = 224 mH and capacitance C = 10.2 μF for the maximum charge on the capacitor to decay to 95.6% of its initial value in 56.0 cycles? (Assume ω′≅ ω.) Number Units
Photons with a wavelength of 549 nm in air enter a plate of flint glass with index of refraction n = 1.66. Find the speed, wavelength, and energy of a photon in the glass. HINT (a) speed (in m/s) m/s (b) wavelength (in m) m (c) energy (in J) J
The figure shows an overhead view of a 0.021 kg lemon half and two of the three horizontal forces that act on it as it is on a frictionless table. Force F→1 has a magnitude of 4 N and is at θ1 = 28∘. Force F→ has a magnitude of 7 N and is at θ2 = 26∘. In unit-vector notation, what is the third force if the lemon half (a) is stationary, (b) has the constant velocity v→ = (10i^ − 16j^)m/s, and (c) has the v→ = (10i^ − 14tj^) m/s2, where t is time? (a) Number i+ j Units (b) Number i+ j Units (c) Number i+ j Units
east. Before After (i) (a) What is the velocity of the truck right after the collision? (Round your answer to at least three decimal places.) 20.829 m/s (east) (b) How much mechanical energy is lost in the collision? J Account for this loss in energy. This answer has not been graded yet.
Give the values for (a) Z and (b) A when 1022 X goes through the β+decay process. Do the same ((c) and (d)) for 814 X. (a) Number Units (b) Number Units (c) Number Units (d) Number Units
Suppose that the sound level of a conversation is initially at an angry 72 dB and then drops to a soothing 53 dB. Assuming that the frequency of the sound is 501 Hz, determine the (a) initial and (b) final sound intensities and the (c) initial and (d) final sound wave amplitudes. Assume the speed of sound is 346 m/s and the air density is 1.21 kg/m3. (a) Number Units (b) Number Units (c) Number Units (d) Number Units
When a certain element is bombarded with high-energy electrons, KaX-rays that have an energy of 5875 eV are emitted. Determine the atomic number Z of the element. Use the Bohr model as necessary. Bohr-model picture of innermost shells of target atom
The force F has a magnitude of 780 N. Express F as a vector in terms of the unit vectors i and j. Identify the x and y scalar components of F. Assume F = 780 N, θ = 15∘. Answers: F = ( i+ j) N Fx = N Fy = N
A force of 6.4 N acts on a 25 kg body initially at rest. Compute the work done by the force in (a) the first, (b) the second, and (c) the third seconds and (d) the instantaneous power due to the force at the end of the third second. (a) Number Units (b) Number Units (c) Number Units (d) Number Units
In the figure the battery has a potential difference of V = 10.0 V and the five capacitors each have a capacitance of 14.0 μF. What is the charge on (a) capacitor 1 and (b) capacitor 2? (a) Number Units (b) Number Units
A cosmic ray proton passes along the left-right width of a page with a relative speed v and total energy 14.35 nJ. According to your measurements, that left-right width is 19.0 cm. (a) What is the width according to the proton's reference frame? How much time did the passage take according to (b) your frame and (c) the proton's frame? (a) Number Units (b) Number Units (c) Number Units
For the circuit in the figure, assume that 8 = 9.00 V, R = 7.50 Ω, and L = 6.50 H. The ideal battery is connected at time t = 0. (a) How much energy is delivered by the battery in the first 3.00 s? (b) How much of this energy is stored in the magnetic field of the inductor? (c) How much of this energy is dissipated in the resistor? (a) Number Units (b) Number Units (c) Number Units
Monochromatic light (wavelength = 499 nm) is incident perpendicularly on a single slit (width = 0.57 mm). A screen is placed parallel to the slit plane, and on it the distance between the two minima on either side of the central maximum is 2.0 mm. (a) What is the distance from the slit to the screen? (Hint: The angle to either minimum is small enough that sinθ ≈tanθ.) (b) What is the distance on the screen between the first minimum and the third minimum on the same side of the central maximum? (a) Number Units (b) Number Units
In the overhead view of the figure, a 360 g ball with a speed v of 8.9 m/s strikes a wall at an angle θ of 20∘ and then rebounds with the same speed and angle. It is in contact with the wall for 9.4 ms. In unit-vector notation, what are (a) the impulse on the ball from the wall and (b) the average force on the wall from the ball? (a) Number i + j Units (b) Number i + j Units
In the overhead view of the figure, a 420 g ball with a speed v of 7.7 m/s strikes a wall at an angle θ of 39∘ and then rebounds with the same speed and angle. It is in contact with the wall for 6.7 ms. In unit-vector notation, what are (a) the impulse on the ball from the wall and (b) the average force on the wall from the ball? (a) Number i + j Units (b) Number i + j Units
The figure below shows two circular regions R1 and R2 with radii r1 = 23.1 cm and r2 = 33.3 cm. In R1 there is a uniform magnetic field of magnitude B1 = 53.4 mT directed into the page, and in R2 there is a uniform magnetic field of magnitude B2 = 75.6 mT directed out of the page (ignore fringing). Both fields are decreasing at the rate of 10.1 mT/s. Calculate ∮E→⋅ds→ for (a) path 1, (b) path 2, and (c) path 3. (a) Number Units (b) Number Units (c) Number Units
The figure below shows two circular regions R1 and R2 with radii r1 = 23.3 cm and r2 = 31.7 cm. In R1 there is a uniform magnetic field of magnitude B1 = 50.6 mT directed into the page, and in R2 there is a uniform magnetic field of magnitude B2 = 76.4 mT directed out of the page (ignore fringing). Both fields are decreasing at the rate of 8.50 mT/s. Calculate ∮E→⋅ds→ for (a) path 1, (b) path 2, and (c) path 3.
In the figure, a particle moves along a circle in a region of uniform magnetic field of magnitude B = 4.6 mT. The particle is either a proton or an electron (you must decide which). It experiences a magnetic force of magnitude 2.8×10−15 N. What are (a) the particle's speed, (b) the radius of the circle, and (c) the period of the motion? (a) Number Units (b) Number Units (c) Number Units
The flexible loop in the figure below has a radius of 14 cm and is in a magnetic field of strength 0.12 T. The loop is grasped at points A and B and stretched until its area is nearly zero. If it takes 0.21 s to close the loop, what is the magnitude of the average induced emf in it during this time? |ε| = mV
Two blocks, each of mass m = 2.85 kg are hung from the ceiling of an elevator as in the figure below. (a) If the elevator moves with an upward acceleration a→ of magnitude 1.1 m/s2, find the tensions T1 and T2 in the upper and lower strings. T1 = N T2 = N (b) If the strings can withstand a maximum tension of 69.4 N, what maximum acceleration can the elevator have before a string breaks? m/s2
A slab of metal has a cross-sectional area of A = 2.61 cm2 and a vertical height of L = 2.00 cm. A magnetic field of B = 0.33 T acts into the slab. The Hall voltage across the vertical height of the slab is 8.00 μV. Assume the conduction electrons can travel through the slab horizontally without being deflected. The current is I = 50.7 A. a) Calculate the Hall electric field EH, in μV/m. b) Calculate the drift velocity of the conduction electrons vd, in millimeters per second: mm/s. c) Calculate the number density n of conduction electrons in the metal. Give your answer in units of electrons per cubic nanometers: e−/nm3.
Assume the three blocks (m1 = 1.0 kg, m2 = 2.0 kg, and m3 = 3.5 kg) portrayed in the figure below move on a frictionless surface and a force F = 36 N acts as shown on the 3.5 kg block. (a) Determine the acceleration given this system (in m/s2 to the right). m/s2 (to the right) (b) Determine the tension in the cord connecting the 3.5 kg and the 1.0 kg blocks (in N). N (c) Determine the force exerted by the 1.0 kg block on the 2.0 kg block (in N). N (d) What If? How would your answers to parts (a) and (b) of this problem change if the 2.0 kg block was now stacked on top of the 1.0 kg block? Assume that the 2.0 kg block sticks to and does not slide on the 1.0 kg block when the system is accelerated. (Enter the acceleration in m/s2 to the right and the tension in N.) acceleration m/s2 (to the right) tension N
A bag of cement weighing 400 N hangs in equilibrium from three wires as suggested in the figure below. Two of the wires make angles θ1 = 55.0∘ and θ2 = 45.0∘ with the horizontal. Assuming the system is in equilibrium, find the tensions T1, T2, and T3 in the wires. T1 = N T2 = N T3 = N
A cord passing over a pulley connects two masses, as shown, where m1 = 2.80 kg and m2 = 6.50 kg. Assume the pulley and surfaces are frictionless, and the cord is massless and does not stretch. (Due to the nature of this problem, do not use rounded intermediate values-including answers submitted in WebAssign-in your calculations.) (4) (a) What is the acceleration of each block? (Enter the magnitude in m/s2.) m/s2 (b) What is the tension in the cord (in N )? N
Consider the Atwood machine shown in the figure, where m1 = 2.00 kg and m2 = 5.10 kg. The system starts at rest, then the sphere is given a quick push downward, giving it an initial speed of 2.80 m/s. Assume the pulley and cord are massless, and the cord is inextensible. Neglect friction. (a) Through what distance (in m) will m1 descend? m (b) What is the velocity (in m/s) of m1 after 1.80 s? magnitude m/s direction -Select--