Question

Pls tell physics 9th sa3 question paper pls 20 points

Answer 1

1) relative density of gold is 19.5 . the density of water is 100okg/m3 . what will be the density of gold in SI units and in g / cc.
2)an echo was heard on a day when teh temperature was about 22 degree celcius. will the echo be heard earlier or later if the temperature falls to 4 degree celcius ? justify your answer.
3)define thrust and pressure. give the  SI unit.
4)calculate the pressure exerted by a block of 45 N if the surface area in contact is 0.5metre square.
5)a geyser of 2.5 KW is used for 8 hours daily. calculate the monthly consumption (30 days) of electric energy units. also calculate teh cost of electricity units consumed in a month if rate per unit is rs.3.50
6)ravi lives in a village and his school is 5 km away from our house.his father suggested him to buy a scooter to go to school but ravi opted for a bicycle.
    a)what kind of energy transformation takes place while ravi rides a bicycle?
    b)what do you conclude about ravi's nature?
    c)suggest one way in which you can contribute to the environment.
7)shop with the help of an example that when a body if dropped from a certain height , the potential energy of the object gets converted into kinetic energy.