A thin copper rod that is 1.0 m long and has a mass of 0.050 kg is in a magnetic field of 0.10 T. What minimum current in the rod is needed in order for the magnetic force to cancel the weight of the rod?
A) 1.2 A B) 7.6 A C) 2.5 A D) 4.9 A E) 9.8 A
D
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An object floats with half its volume beneath the surface of the water. The weight (force that Earth exerts in it) of the displaced water is 2000 N
What is the weight (force that Earth exerts on it) of the object? The density of water is 1000 kg/m3. A) 1000 N B) 2000 N C) 4000 N D) It cannot be determined because we do not know the volume of the object.
An automobile traveling along a straight road increases its speed from 30.0 m/s to 50.0 m/s in a distance of 180 m. If the acceleration is constant, how much time elapses while the auto moves this distance?
a. 6.00 s b. 4.50 s c. 3.60 s d. 4.00 s e. 9.00 s
Gravitational equilibrium means that the surface and the core of the Sun are at the same pressure
Indicate whether the statement is true or false
An 8.0-m massless rod is loosely pinned to a frictionless pivot at 0, as shown in the figure. A very small 4.0-kg ball is attached to the other end of the rod
The ball is held at A, where the rod makes a 30° angle above the horizontal, and is released. The ball-rod assembly then swings freely with negligible friction in a vertical circle between A and B. The tension in the rod when the ball passes through the lowest point at D is closest to A) 160 N. B) 200 N. C) 120 N. D) 80 N. E) 40 N.