Question 1 :
<img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d2e1f59b460d7261f64a.png' /> Look at the above image. In each of the following a force, F is acting on an object of mass, m. The direction of displacement is from west to east shown by the longer arrow. Observe the diagrams carefully and state whether the work done by the force is negative, positive or zero resctively.

Question 2 :
State true or false : There can be displacement of an object in the absence of any force acting on it.

Question 3 :
An automobile engine propels a 1000 kg car along a levelled road at a speed of $36 kmh^{–1}$. Find the power if the opposing frictional force is 100 N.

Question 5 :
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?

Question 6 :
Kamali is preparing for examinations. She spends lot of time in studies. She reads lots of books. In common parlance, she is ‘working hard’. But is it really a work?

Question 8 :
A pair of bullocks exerts a force of 140 N on a plough. The field being ploughed is 15 m long. How much work is done in ploughing the length of the field?

Question 9 :
Calculate the work required to be done to stop a car of 1500 kg moving at a velocity of 60 km/h?

Question 10 :
Avinash can run with a speed of $8 ms^{-1}$ against the frictional force of 10 N, and Kapil can move with a speed of $3 ms^{–1}$ against the frictional force of 25 N. Who is more powerful and why?