Physics Ch 7

the power required to exert a 4-N force over 3 meters in 2 seconds is

the work you do when pushing a shopping cart twice as far while applying twice the force is

hydro and wind power are indirect forms of

a roller skate at rest may have

relative to an initial height, an object raised twice as high has a gravitational potential energy that is

when Joshua brakes his speeding bicycle to a stop, kinetic energy is transformed to

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

an object that has kinetic energy must be

a 2 kg ball is held 4m about the ground. Relative to the ground its potential energy is

two identical arrows, one with twice the speed of the other, are fired into a bale of hay. Compared with penetration of the slow arrow, the faster arrow penetrates

which task requires more work a. lifting the 25 kg sack 4 meters b. both the same c. lifting the 50 kg sack 2 meters d. need more information

the power expended doing 100J of work in 50 s is

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

a machine puts out 100 watts of power for every 1000 watts put into it. The efficiency of the machine is

a ball rolling down an incline has its maximum kinetic energy at

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

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

a hydraulic press has its input piston depressed 20 cm while the output piston is raised 1 cm. A 1 N input can lift a load of

which has greater kinetic energy a. a car half the mass traveling at 60 km/hr b. need more information c. a car traveling at 30 km/hr d. both the same

a 2 kg box of taffy candy has 40 J of potential energy relative to the ground. Its height above the ground is

danny diver weighs 500 N and steps off a diving board 10 m above the water. Danny hits the water with kinetic energy of

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

a ball rolling down an incline has its maximum potential energy at

an object has gravitational potential energy due to its

a primary difference between momentum and kinetic energy is

strictly speaking, more fuel is consumed by your car if the air conditioner, headlights, or even a radio is turned on. This statement is

when wind encounters a wind turbine that produces energy, wind speed on the downside of the blades is

phil applies 100 N to a pulley system and raises a load one-tenth of his downward pull. Ideally, the weight of the load is

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

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

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

a clerk can lift cylindrical packages 1 meter vertically, or can roll them up a 2 meter long ramp to the same elevation. With the ramp, the applied force required is about

two identical golf carts move at different speeds. The faster cart has twice the speed and therefore has

the work you do when pushing a shopping cart a given distance while applying twice as much force is

when a drawn bow of potential energy 40 J is fired, the arrow will ideally have a kinetic energy

the work you do when pushing a shopping cart twice as far while applying the same force is

the bob of a simple pendulum has its maximum kinetic energy at the

a 1000 kg car and a 200 kg car are hoisted to the same height. Raising the more massive requires

two 2-m/s pool balls roll toward each other and collide. Suppose after bouncing apart each moves at 4m/s. this collision violates the conservation of

a circus diver drops from a high pole into water far below. When he is halfway down a. he has gained an amount of kinetic energy equal to has his initial PE b. none of the choices c. all choices are correct d. his PE is halved e. his KE and PE are equal

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

earths primary energy source is

the work done is pushing a TV set a distance of 2m with an average force of 20 N is