A box weighing 4 lbs. is on a frictionless surface in circular motion with a radius of 2 ft. from the center post and a tangential velocity of 5 ft/sec. Suddenly at point A the rope holding the box to the post starts to be retracted at a velocity of 4 ft/sec. What is the speed of the box at point B, where the radius has reduced to 1 ft.? After pulling the rope in from A to B, how much work was done? You may neglect the mass of the rope and the size of the box.

The us government wants to allocate billions of dollars in the next 10 years to assure our future energy security. the funds will be spread among a variety of possible energy resources. where do you think the government should put the greatest support: solar energy, wind energy, clean coal, oil exploration, gas exploration, or a combination of sources? are there other efforts that should be explored? support your position with cited information for both questions.

Astudent pushes on a 20.0 kg box with a force of 50 n at an angle of 30° below the horizontal. the box accelerates at a rate of 0.5 m/s2 across a horizontal floor. what is the value of the normal force on the box? 200 n 243 n 156 n 225 n

Use the right-hand rule for magnetic force to determine the charge on the moving particle. this is a charge.