Class 11 ( Force and laws of motion & work energy and power)

 Questions on Force and laws of motion & Work, energy and power 

Q.1 Derive mathematical formula of  conservation of momentum? 

2. A women stands on a spring scale on an elevator. In which case will the scale record the minimum reading and the maximum reading ? (A) elevator accelerating upwards (B) elevator cable breaks , free fall 

3. State and prove Impulse momentum theorem

4. A force of 100N gives a mass m1 an acceleration of 10 m/ s², and of 20 m/s² to a mass m2. What acceleration would it give if both the masses are tied together? 

5. The momentum of a body is increased by 50%. What is the percentage change in its KE? 

6. Derive the relation b/w 1J and 1erg .

7. State and derive work energy theorem 

8. A bullet of mass 20g moving with a velocity of 500 m/s strikes a tree and goes out from the other end with a velocity of 400 m/s. Calculate the work done in passing through the tree. 

9 An engine draws a train up an incline of 1 in 100 at the rate of 36 km/h. If the resistance through the friction is 5kg wt per ton, calculate the power of the engine. If mass of the train and engine is 100. 

10. An iron sphere of mass of 1 kg is dropped from a height of 10m. If the acceleration of sphere is 9.8 m/s² calculate the momentum transferred to the ground by the ball.