How long does it take electrons to get from a car battery to the starting motor? Assume the current is 340 A and the electrons travel through a copper wire with cross-sectional area 0.260 cm2 and length 0.890 m. The number of charge carriers per unit volume is 8.49×1028 m−3. Number Unit
A crate having a mass of 60.0 kg is sliding on a level surface as shown in the figure. (i) A worker exerts a force of magnitude Fapp = 85.0 N on the block at an angle of 45.0∘ below the horizontal. Calculate the magnitude of the force of kinetic friction (in N) exerted by the surface on the crate. (The coefficient of kinetic friction between the crate and surface is 0.150.) The local free-fall acceleration is 9.80 m/s2. (Enter the magnitude.) N
A small electric car applies a force of 650 N in the positive x-direction to a sledge of mass m = 170 kg as shown in the figure. If the surface is level with a kinetic friction coefficient of 0.150, find the acceleration (in m/s2). (The local free-fall acceleration is 9.80 m/s2. Indicate the direction with the sign of your answer.) m/s2
A student is pulling a crate with a mass of 20.0 kg along a horizontal rough floor with a rope that's inclined at an angle θ = 30.0∘ above the horizontal as shown. The tension force is measured to be 150 N. The coefficients of friction between the crate and the floor are μs = 0.35 and μk = 0.20. What is the magnitude of the acceleration of the crate, in m/s2? Use g = 10.0 m/s2. ((Compare the result from the previous homework when there was no friction, does the answer make sense?) Your answer needs to have 2 significant figures, including the negative sign in your answer if needed. Do not include the positive sign if the answer is positive. No unit is needed in your answer, it is already given in the question statement.
A 44.3−kg crate rests on a horizontal floor, and a 74.8−kg person is standing on the crate. Determine the magnitude of the normal force that (a) the floor exerts on the crate and (b) the erate exerts on the person. (a) Number Units (b) Number Units
A train car of mass m = 20,000 kg is connected by a horizontal coupling to a second train car of mass M = 19,000 kg on a level, frictionless surface as shown in the figure. If a train engine applies a horizontal force of 1.05×105 N in the positive x-direction to the train car of mass M, find the acceleration of the system. (Enter your answer in m/s2. Indicate the direction with the sign of your answer.) m/s2
The drawing shows three particles far away from any other objects and located on a straight line. The masses of these particles are mA = 325 kg, mB = 580 kg, and mC = 125 kg. Take the positive direction to be to the right. Find the net gravitational force, including sign, acting on (a) particle A, (b) particle B, and (c) particle C. (a) Number Units (b) Number Units (c) Number Units
In the figure R1 = 120 Ω, R2 = R3 = 42.0 Ω, R4 = 75.6 Ω, and the ideal battery has emf ε = 6.00 V. (a) What is the equivalent resistance? What is i in (b) resistance 1, (c) resistance 2, (d) resistance 3, and (e) resistance 4? (a) Number Units (b) Number Units (c) Number Units (d) Number Units (e) Number Units
Two particles are fixed to an x axis: particle 1 of charge q1 = 1.98×10−8 C at x = 28.0 cm and particle 2 of charge q2 = −5.76q1 at x = 64.0 cm. At what coordinate on the x axis is the electric field produced by the particles equal to zero? Number Units
Three Blocks: Three blocks, each of mass 13 kg are on a frictionless table. A han pushes on the left most block (block A) such that the three boxes accelerate in the positive horizontal direction as shown at a rate of a = 0.7 m/s?. (a) What is the magnitude of the force on block A from the hand? (b) What is the net horizontal force on block A? (c) What is the horizontal force on block A due to block B? (d) What is the net horizontal force on block B? (e) What is the horizontal force on block B due to block C?
A magnetic field has a magnitude of 0.0011 T, and an electric field has a magnitude of 5.5×103 N/C. Both fields point in the same direction. A positive 1.7−μC charge moves at a speed of 4.3×106 m/s in a direction that is perpendicular to both fields. Determine the magnitude of the net force that acts on the charge. Number Units
A delivery person carries a stack of three boxes labeled 1, 2, and 3, with box 3 on the bottom of the stack and box 1 on the top. The masses of boxes 1, 2, and 3 are m1 = 1.54 kg, m2 = 2.56 kg, and m3 = 6.80 kg, respectively. The delivery person places the stack of boxes on an elevator floor, which then accelerates downward with a magnitude of a = 0.96 m/s2. Let g = 9.81 m/s2 denote the acceleration due to gravity, and let the positive y-direction be upward. Calculate the contact force F→1→2 that box 1 exerts on box 2 during the acceleration. F→1→2 = j^ N Calculate the contact force F→3→2 that box 3 exerts on box 2 during the acceleration. F→3→2 = j^ N