# Physics

A mechanical device requires 420 J of work to do 230 J of work in lifting a crate. What is the efficiency of the device?
I keep getting 0.5% am I right?

1. 👍
2. 👎
3. 👁
1. Eff. = (Output/Input)*100% =(230/420)*100 = 54.8%

1. 👍
2. 👎
2. I am wondering the same thing

1. 👍
2. 👎

## Similar Questions

can someone check my answer thanks ! 2.The ability to do work or cause change is called A.velocity. B.energy.(I PICK B.) C.transfer. D.friction. 3.Which type of energy is demonstrated by a person jogging? A.electrical energy

2. ### Physics

How much work is done when a mass of 3 kg (weighing 30 N) is lifted vertically through 6 m?. A hiker climbs a hill 300 m high. If she has a mass of 50 kg calculate the work she does in lifting her body to the top of the hill.

3. ### physics

A 1-kg block is lifted vertically 1m by a boy. The work done by the boy would be one jule or would no work be done. I'm confused, I thought lifting wasn't considered work. The work done is actually about 9.81 joules. Think of

4. ### Physics

A machine with v.r of 5 requires 1000No of work to raise a load of 500N through a vertical distance of 1.5. ( a ) find the efficiency of the machine. (B) calculate it's mechanical advantage

1. ### Physics

you lift a chair that weighs 50 n to a height of 0.5cm and carry it 10 m across the room how much work do you do on the chair. I just want to make sure is it 25J because you are only doing work if you are lifting it but walking

2. ### Math

A work crew of 3 people requires 3 weeks and 2 days to do a certain job. How long would it take a work crew of 4 people to do the same job if each person of both crews works at the same rate as each of the others? Note: each week

3. ### Physics

What is the work done in lifting 60 kg of blocks to a height of 20m?

4. ### physics

A machine with a velocity ratio requires 1000J of work to raise a load of 500N through a vertical distance of 1.7m . find the efficiency and mechanical advantage of the machine.

1. ### Physics

Select which of the following statements are True or False. Assume Newtonian Mechanics. 1.The work required to lift a mass one meter depends on the speed at which it is raised.. 2.The acceleration of an object is same in all

2. ### Science

A generator transforms A. Potential energy into kinetic energy B. mechanical energy into electrical energy***** C. Magnetic energy into electrical energy D. Friction into electrical energy Electrical charges that are different A.

3. ### physics

which is more work pushing with 115N over 15 m or lifting 20N 10meters

4. ### Physics

An object of mass .550kg is lifted from the floor to a height of 3.5m at a constant speed. How much work is done by the lifting force (include units)? b.) How much work is done by the Earth on the object? c.) What is the net work