# physical science

if an engine must do 500 joules to pull a 10 kg load up to a height of 4 meters, what is the efficiency of the engines?

1. 👍
2. 👎
3. 👁
1. The useful work done (the potential energy increase) is M g H = 392 J

The efficiency is (Work out)/(Work in) = 392/500 = __ %

1. 👍
2. 👎

## Similar Questions

1. ### math

Erica found the mean of the yearly incomes of a sample of households in her hometown as shown in the chart below. In a report, she stated, she stated, "the typical income in my neighborhood is about \$81,500 per year." How is this

2. ### physics

A simple lever is used to lift a heavy load. When a 60-N force pushes one end of the lever down 1.2 m, the load rises 0.2 m. Show that the weight of the load is 360 N.

3. ### physics

What amount of heat is required to raise the temperature of 20 grams of water from 10°C to 30°C? The specific heat of water is 4.18 J/g°C. 1200 joules 1500 joules 1700 joules 1900 joules 2000 joules

4. ### physics

You're in an airplane that flies horizontally with speed 860 km/h (240 m/s ) when an engine falls off. Neglecting air resistance, assume it takes 26 s for the engine to hit the ground. Hight of airplane is: H = 3.3 km horizontal

1. ### physics

If you pull one end of the rope 1.0 m downward with a 50 N force, find the height you can lift a 150 N load.

2. ### Physics

The efficiency of a machine is 60℅,find In joules the work done by a student using the machine to rise a load of 150kg through a vertical distance or 2.5 m (g=10m/s2)

3. ### Physics

A heat engine exhausts 3 000 J of heat while performing 1 500 J of useful work. What is the efficiency of the engine?

4. ### Physics

A person pushes a box. He applies a force of 400 newtons, and he pushes the box for a distance of 4 meters. After he stops pushing, the box slides forward another meter. How much work was done by the person? • 100 joules •

1. ### physics

15 joules of work are done by forces other than gravity in taking an object from a position 3 m above the ground to a position 8 m above the ground. What is the change in the gravitational potential energy of the object? o A. It

2. ### physics

A worker can supply a maximum pull of 150 lbs. on a cart which has a handle set an angle of 40degree above the horizontal. what is the coefficient of friction if he can just move a total load of 1500lbs. ?

3. ### Science

A 54-kg jogger is running at a rate of 3m/s. What is the kinetic energy of the jogger. A. 18 Joules B. 81 Joules C. 162 Joules D. 243 Joules

4. ### Physics

What amount of heat is required to raise the temperature of 350 grams of copper to cause a 25°C change? The specific heat of copper is 0.39 J/g°C A. 2500 joules B. 2600 joules C. 3400 joules D. 3900 joules