Physics Notes Pt. 2

Physics Notes Pt. 2 The work you do when pushing a shopping cart twice as far while applying twice the force is - four times as much When wind encounters a wind turbine that produces energy, wind speed on the downside of the blades is - slowed A hydraulic jack is used to lift objects such as automobiles. If the input force is 200 N over a distance of 1 meter, the output force over a distance of 0.1 meter is ideally - 2000 N. Which task requires more work? - both require the same Strictly speaking, more fuel is consumed by your car if the air conditioner, headlights, or even a radio is turned on. This statement is - true Two identical golf carts move at different speeds. The faster cart has twice the speed and therefore has - four times the kinetic energy. If a Ping-Pong ball and a golf ball both move in the same direction with the same amount of kinetic energy, the speed of the Ping-Pong ball must be - more than the golf ball. A crate of grapes lifted 10 meters gains 200 J of potential energy. If the same crate is instead lifted 20 meters, its gain in potential energy is - twice as much. A melon is projected into the air with 100 J of kinetic energy in the presence of air resistance. When it returns to its initial level its kinetic energy is - less than 100 J. A 1-kg ball dropped from 2 m rebounds only 1.5 m after hitting the ground. The amount of energy converted to heat is about - more than 2.0 J. About 40 J is required to push a crate 4 m across a floor. If the push is in the same direction as the motion of the crate, the force on the crate is about - 10 N Danny Diver weighs 500 N and steps off a diving board 10 m above the water. Danny hits the water with kinetic energy of - 5000 J. Neglecting air resistance, Sammy Smarts on a high ladder releases a ball that strikes the ground with 100 J of kinetic energy. If he were to instead throw the ball straight upward, it will soon reach the ground with a kinetic energy of - 1OO J Which has greater kinetic energy? - a car of half the mass traveling at 60 km/hr A block of ice sliding down an incline has half its maximum kinetic energy - halfway down. A motorcycle moving at 50 km/h skids 10 m with locked brakes. How far will it skid with locked brakes when traveling at 150 km/h? - 90 m Two identical arrows, one with twice the kinetic energy of the other, are fired into a bale of hay. Compared with penetration of the slow arrow, the faster arrow penetrates - twice as far. A 2-kg ball is held 4 m above the ground. Relative to the ground its potential energy is - 80 J. The amount of work done on a heavy box carried by Nellie across a room at a constant speed - is none. The power required to exert 4-N force over 3 meters in 2 seconds is - 6 W. A toy elevator is raised from the ground floor to the second floor in 20 seconds. The power needed using 1000 J of work, is - 50 W. A moving object has - all of these A ball rolling down an incline has its maximum potential energy at - the top. A 2500-N pile-driver ram falls 10 m and drives a post 0.1 m into the ground. The average impact force on the ram is - 250,000 N. .The work you do when pushing a shopping cart a given distance while applying twice as much force is - twice as much Which requires the most amount of work by the brakes of a car? - slowing down from 100 km/h to 70 km/h If you do work on a skateboard loaded with friends in one-third the usual time, you expend - three times the usual power. The power expended doing 100 J of work in 50 s is - 2 W. A melon is tossed straight upward with 100 J of kinetic energy. If air resistance is negligible the melon will return to its initial level with a kinetic energy of - 100 J. A hydraulic press has its input piston depressed 20 centimeters while the output piston is raised 1 centimeter. A 1-newton input can lift a load of - 20 N. A machine puts out 100 watts of power for every 1000 watts put into it. The efficiency of the machine is - 10%. When Joshua brakes his speeding bicycle to a stop, kinetic energy is transformed to - heat A roller skate at rest may have - energy A circus diver drops from a high pole into water far below. When he is halfway down - all of the above Both a 50-kg sack is lifted 2 meters from the ground and a 25-kg sack is lifted 4 meters in the same time. The power expended in raising the 50-kg sack is - the same When you and your snowboard are in motion, which of the following can be zero? - none of the above When a drawn bow of potential energy 40 J is fired, the arrow will ideally have a kinetic energy - of 40 J Two identical particles move toward each other, one twice as fast as the other. Just before they collide, one has a kinetic energy of 25 J and the other 50 J. At this instant their total kinetic energy is - 75 J The unit kilowatt-hour is a unit of - energy Acrobat Bart at the circus drops vertically onto the end of a see-saw, with his partner Art equidistant from the fulcrum at the other end. Art is propelled straight upward a distance twice that of Bart's dropping distance. Neglecting inefficiencies we see - Art has half the mass of Bart. A 1000-kg car and a 2000-kg car are hoisted to the same height. Raising the more massive car requires - twice as much work. A jack system will increase the potential energy of a heavy load by 1000 J with a work input of 2000 J. The efficiency of the jack system is - 50%. The ram of a pile driver drops onto the top of an iron beam, driving it partway into the ground. The distance that the beam sinks into the ground depends on the - all of the above One kilowatt-hour represents - 3.6 million joules. A ball rolling down an incline has its maximum kinetic energy at - the bottom. A bicycle that travels four as fast as another when braking to a stop will skid - sixteen times as far After rolling halfway down an incline, a marble's kinetic energy is - the same as its potential energy A 2-kg box of taffy candy has 40 J of potential energy relative to the ground. Its height above the ground is - 2m Relative to an initial height, an object raised twice as high has a gravitational potential energy - twice as much Impulse involves the time that a force acts, whereas work involves the - distance that a force acts A primary difference between momentum and kinetic energy is - momenta can cancel; kinetic energy cannot. A cannonball has more kinetic energy than the recoiling cannon from which it is fired because the force on the ball - acts over a longer distance.