Subject: Physics, asked on 25/1/21

## The distance between Chembur, Mumbai and Kothrud, Pune is 150 km. I start driving from Kothrud at 7:00 a.m. and travel towards Chembur at 80 km/hr. My wife starts driving from Chembur at 7:30 a.m. and travels towards Kothrud at 70 km/hr. At what time will we cross each other??

Subject: Physics, asked on 7/11/12

## CLASS—IX Physics Assignment WORK, ENERGY AND POWER1. Under what conditions work is said to be done?2. Derive the formula for work done by a constant force3. Give few examples where energy is possessed by a body due to its change in shape.4. State and prove the law of conservation of energy.5. Is it possible that force is acting on a body but still work done is zero? Explain.6. A rocket of mass3x106kg takes off from a launching pad and acquires a verticalvelocity of 1km/s at an altitude of 25 km. calculate (a) the potential energy and (b) thekinetic energy. (g = 9.8m/s2)7. If a man lifts a load up with the help of a rope such that it raises the load of mass 50kgto a height of 20m in 100 sec. Find the power of man8. A ball is dropped from a height of 5m. Find the velocity of the ball just before itreaches the ground. Do you require the value of mass to find the velocity?9. Two persons A and B do same amount of work. The person A does that work in t1secand the person b in t2sec. Find the ratio of power delivered by them.10. Why do our hands become warm when rubbed against each other? Explain.11. The kinetic energy of a body of mass 15 kg is 30J. What is its momentum?12. Give an example for each of the following energy conversion: (1) electrical energy tokinetic energy. (2) Chemical energy to electrical energy (3) sound energy to electricalenergy13. Two bodies have same momentum. Which will have greater kinetic energy- heavierbody or lighter body?14. An electric bulb of 60w is used for 6h per day .Calculate the units of energyconsumed in one day by the bulb.15. A boy of mass 50kg runs up to a stair case of 45 steps in 9s. If the height of a step is15cm, find his power. (g= 10m/s2)16. Two particles of masses 1g and 2g have equal momentum. Find the ratio betweentheir kinetic energies?17. What will be the work done by the string, when a stone is tied to a string and whirledin a circle?18. A locomotive exerts a force of 7500N and pulls a train through 1.5 km. How muchwork is done by locomotive?19. What work a boy of mass 50kg will do in order to increase running speed from9km/h to 18km/h.20. The speed of a moving body is halved. What is the change in its K.E.?21. State the energy changes taking place in the following cases: (1) A car moves up ahilly road.(2) a stone projected vertically upward returns22. When we cut a log of wood with a saw it becomes warm, why?23. If an electric iron of 1200W is used for 30 minutes everyday, find electric energyconsumed in the month of April.

Subject: Physics, asked on 7/10/14

## A machine is operated by an effort of 80N acting downward and moving through a downward displacement of 015m. The load of mass 10kg is raised up by 10cm. Calculate:1) mechanical advantage2) velocity ratio 3)work input 4)useful work output 5)efficiency

Subject: Physics, asked on 14/5/20

## a 280 gram toy does 12 push-ups in a minute, displacing its centre of mass by a distance of 5.5 cm for each push-up. determine the total work done by the toy while moving downward.

Subject: Physics, asked on 12/8/18

## Differentiate between nuclear fission and nuclear fusion

Subject: Physics, asked on 30/1/15

## A particle moves on the x axis. When its acceleration is positive and increasing:A. its velocity must be positiveB. its velocity must be negativeC. it must be slowing downD. it must be speeding upE. none of the above must be trueans: E....explain

Subject: Physics, asked on 21/11/18

## What is the Centre of Gravity of A Cuboid?

Subject: Physics, asked on 15/12/13

## Raghav applies a force of 6kgf to draw 4.8kg bucket of water from a well using a single fixed pulley. Assuming that all of the extra force a applied is to overcome frictional forces, calculate the force of friction, mechanical advantage and efficiency.

Subject: Physics, asked on 16/11/20

## What is meant by advance sunrise and delayed sunset... Draw a labelled diagram to explain these phenomena..

Subject: Physics, asked on 4/6/12

## a metallic wire has a resistance of 1 ohm per meterfind the total resistance of4 times the length of the wirewhat will be the resistance of a 2.5 m long wirewhat will be the resistance of 6 m length of long wire of the same material but with4 times the area of cross section

Subject: Physics, asked on 15/6/12

## why speed of light increases with increase with temperature?

Subject: Physics, asked on 15/6/16

## Suppose you are given three resistances of values 2,4,6 ohms. Which of the following value is not possible to get by arranging resistances in various combinations =>>>> (a) Less than 2 ohms (b) Equal to 4.4 ohms (c) Equal to 7.33 ohms (d) Equal to 6.75 ohms

Subject: Physics, asked on 13/5/15

## a car starting from rest has a constand acceleration a1 for a time t1 during which it covers a distance s1. in the next tine interval t2 the car has a constant retardation a2 and comes to rest after covering a distance s2 in th etime comes to rest after covering a distance s2 in the time t2what would reltation in them

Subject: Physics, asked on 6/11/13

## what is disadvantage of water having high specific heat capacity?

Subject: Physics, asked on 17/2/19

## A sound wave of frequency 4 khz and wavelength 25 cm is travelling in a liquid. What will be the time taken by the sound wave to cover a distance of 1.2km in the liquid?

What are you looking for?