Which of the following is true about a planet orbiting a star in uniform circular motion? a. the direction of the velocity vector is always changing. b. the velocity of the planet is constant. c. the speed of the planet is always changing. d. the acceleration vector of the planet points directly away from the star.

Mike walks 100 meter north, then walks 30 meters south. after this, he walks another 10 meters north. what is the magnitude of his total displacement during this walk,in meters?

It may seem strange that the selected velocity does not depend on either the mass or the charge of the particle. (for example, would the velocity of a neutral particle be selected by passage through this device? ) the explanation of this is that the mass and the charge control the resolution of the device--particles with the wrong velocity will be accelerated away from the straight line and will not pass through the exit slit. if the acceleration depends strongly on the velocity, then particles with just slightly wrong velocities will feel a substantial transverse acceleration and will not exit the selector. because the acc

If a hiker that weighs 600 newtons climbs a 50 meter hill, how much gravitational potential energy has the hiker gained?