An object thrown at a certain angle to the ground moves in a curved path and falls back to the ground. The initial and the final points of the path of the object lie on the same horizontal line. What is the work done by the force of gravity on the object?
Solution and Explanation
For calculating work done there must be displacement but since in this example vertical displacement is zero (as initial and final points lie on the same horizontal line) so the work done by force of gravity is zero.
Top Questions on Work
- In an actual regenerative Rankine cycle, the net work out put will be _____ as compared to simple Ranking cycle.
- A metal has work function \(w_0\) = 3.3×10-19 J. What should be the minimum frequency of the incident radiation that can remove an electron from the metal surface? [Given h = 6.6x10-34 J-s]
- Look at the activities listed below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
• Suma is swimming in a pond.
• A donkey is carrying a load on its back.
• A wind-mill is lifting water from a well.
• A green plant is carrying out photosynthesis.
• An engine is pulling a train.
• Food grains are getting dried in the sun.
• A sailboat is moving due to wind energy. - An object of mass, m is moving with a constant velocity, v. How much work should be done on the object in order to bring the object to rest?
- Calculate the work required to be done to stop a car of 1500 kg moving at a velocity of 60 km/h?
Questions Asked in CBSE Class IX exam
- The author speaks both of people who were very aware of the differences among them and those who tried to bridge these differences. Can you identify such people in the text?
- CBSE Class IX
- My childhood
- Explain what the reasons for the following are.
(i) Einstein leaving the school in Munich for good.
(ii) Einstein wanting to study in Switzerland rather than in Munich.
(iii) Einstein seeing in Mileva an ally.
(iv) What do these tell you about Einstein?- CBSE Class IX
- A truly beautiful mind
- (i) The kind of person the doctor is (money, possessions)
(ii) The kind of person he wants to be (appearance, ambition)- CBSE Class IX
- The snake and the mirror
In Fig. 9.26, A, B, C and D are four points on a circle. AC and BD intersect at a point E such that ∠ BEC = 130° and ∠ ECD = 20°. Find ∠ BAC.
- CBSE Class IX
- Angle Subtended by an Arc of a Circle
- Name the two temples the author visited in Kathmandu.
- CBSE Class IX
- Kathmandu
Concepts Used:
Work
Work is the product of the component of the force in the direction of the displacement and the magnitude of this displacement.
Work Formula:
W = Force × Distance
Where,
Work (W) is equal to the force (f) time the distance.
Work Equations:
W = F d Cos θ
Where,
W = Amount of work, F = Vector of force, D = Magnitude of displacement, and θ = Angle between the vector of force and vector of displacement.
Unit of Work:
The SI unit for the work is the joule (J), and it is defined as the work done by a force of 1 Newton in moving an object for a distance of one unit meter in the direction of the force.
Work formula is used to measure the amount of work done, force, or displacement in any maths or real-life problem. It is written as in Newton meter or Nm.