A wire carrying a 30.0-A current passes between the poles of a strong magnet that is perpendicular to its field and experiences a 2.16−N force on the 4.00 cm of wire in the field. What is the average field strength? 2.60 T 1.80 T 4.40 T 3.40 T
A strip of copper is placed in a uniform magnetic field of magnitude 2.5 T. The Hall electric field is measured to be 1.5×10−3 V/m. What is the drift speed of the conduction electrons? 5.0×10^−4 m/s 7.0×10^−4 m/s 8.0×10^−4 m/s 6.0×10^−4 m/s
(a) What is the maximum torque on a 150-turn square loop of wire 18.0 cm on a side that carries a 50.0-A current in a 1.60−T field? (b) What is the torque when θ is 10.9∘ ? Find the current through a loop needed to create a maximum torque of 9.00 N⋅m. The loop has 50 square turns that are 15.0 cm on a side and is in a uniform 0.800− T magnetic field. Calculate the magnetic field strength needed on a 200-turn square loop 20.0 cm on a side to create a maximum torque of 300 N⋅m if the loop is carrying 25.0 A.
What pressure is exerted on the bottom of a gas tank that is 0.500−m wide and 0.900−m long and can hold 50.0 kg of gasoline when full? 3.06×10^3 N/m^2 1.09×10^3 N/m^2 2.00×10^3 N/m^2 4.20×10^3 N/m^2
What force must be exerted on the master cylinder of a hydraulic lift to support the weight of a 2000-kg car (a large car) resting on a second cylinder? The master cylinder has a 2.00−cm diameter and the second cylinder has a 24.0−cm diameter. 150 N 200 N 136 N 180 N
How tall must a water-filled manometer be to measure blood pressure as high as 300 mmHg? Density of blood is 1.05×103 kg/m3 4.08 m 1.36 m 5.05 m 7.60 m
What fraction of ice is submerged when it floats in freshwater, given the density of water at 0∘C is very close to 1000 kg/m3 ? 20% 95% 91.7% 80%
Calculate the retarding force due to the viscosity of the air layer between a cart and a level air track given the following information: air temperature is 20∘C, the cart is moving at 0.400 m/s, its surface area is 2.50×10−2 m2, and the thickness of the air layer is 6.00×10−5 m. Viscosity of air at 20∘C is 1.516×10−5 Pas 3.07×10^−3 N 9.605×10^−3 N 2.503×10^−3 N 6.500×10^−3 N