A machine is supplied energy at a rate of 4000 watts and does useful work at a rate of 3761 watts what

is the efficiency of the machine

Which best describes the energy used to pluck guitar strings to make sound?

A 2.3 kg box, starting from rest, is pushed up a ramp by a 10 N force parallel to the ramp. The ramp is 2.0 m long and tilted at 17â. The speed of the box at the top of the ramp is 0.80 m/s.

force of 50 N is applied to a 100 kg boulder, which starts at rest and moves 5.5 meters accross a level frictionless cliffside that is 12 meters high. How fast is the boulder moving when it leaves the cliff?

10 How are bacterial cells different from plant and animal cells? A Bacterial cells Bacterial cells contain many more cell organelles. Bacterial cells contain almost no cell organelles. Bacterial cells have more complex cell organelles.

Which waves are mechanical waves? A. microwaves B. sound waves C. light waves D. radio waves

As part of his meal, a workman has a cup containing a hot drink. In order to keep the drink hot whilst he eats the rest of his meal, he covers the cup, as shown in the figure. Which sources of energy loss does this action reduce? Tick two boxes.

When energy is transformed, the amount of usable energy?

If an object weighs 39.2 n on earth, what is its mass

What happens when pressure is applied to a solid.

A box of mass 1 kg is hung from a spring scale. The reading on the spring scale is approximately 10N. What would be the reading on the spring scale if a box of mass 5 kg is hung from it? (Assume acceleration due to gravity to be 10 m/s2.