Advertisements
Advertisements
Question
What is the work done by the force of gravity on a satellite moving round the earth? Justify your answer.
Advertisements
Solution
When a satellite orbits the earth, its displacement over a short period of time is along the tangent to the satellite's circular route. The gravitational force (F) exerted on the satellite due to the earth is along the radius depicted in the picture.
Because a tangent is always perpendicular to the radius, both displacement and force are perpendicular. The satellite experiences no displacement in the direction of the force, i.e., s = 0. As a result, the force of gravity on the satellite produces no work since W = F × s = 0.
RELATED QUESTIONS
A lamp consumes 1000 J of electrical energy in 10 s. What is its power?
Define average power.
What is the power of a body which is doing work at the rate of one joule per second?
Fill in the blank with suitable word :
Power is the rate of doing ___________.
A man weighing 500 N carried a load of 100 N up a flight of stairs 4 m high in 5 seconds. What is the power?
The power output of an engine is 3kW. How much work does the engine do in 20 s?
An electric heater uses 600 kJ of electrical energy in 5 minutes. Calculate its power rating.
A car of weight 20000 N climbs up a hill at a steady speed of 8 m/s, gaining a height of 120 m is 100 s. Calculate : power of engine of car.
Define power. Give the SI unit of power.
In loading a truck, a man lifts boxes of 100 N each through a height of 1.5 m.
If the man lifts 4 boxes per minute, at what power is he working?
(g = 10 m s−2)
