English Medium इयत्ता ९ - CBSE Question Bank Solutions

An object is put in three liquids having different densities, one by one. The object floats with `1/9` , `2/11` and `3/7` parts of its volume outside the surface of liquids of densities d₁, d₂ and d₃ respectively. Which of the following is the correct order of the densities of the three liquids?

A metal in which even iron can float is :

The relative densities of four liquids P, Q, R and S are 1.26, 1.0, 0.84 and 13.6 respectively. An object is floated in all these liquids, one by one. In which liquid the object will float with its maximum volume submerged under the liquid?

A solid of density 900 kg/m³ floats in oil as shown in the given diagram. The oil floats on water of density 1000 kg/m³ as shown. The density of oil kg/m³ could be :

The density of water is 1000 kg/m3 and the density of copper is 8900 kg/m3. Which of the following statements is incorrect?

The diagrams represent four measuring cylinders containing liquids. The mass and volume of the liquid in each cylinder are stated. Which two measuring cylinder could contain an identical liquid?

Calculate the work done by the brakes of a car of mass 1000 kg when its speed is reduced from 20 m/s to 10 m/s?

A body of mass 100 kg is lifted up by 10 m. Find :
(i) the amount of work done
(ii) potential energy of the body at that height (value of g = 10 m/s²)

How much is the mass of a man if he has to do 2500 joules of work in climbing a tree 5 m tall? (g = 10 m s⁻²)

Fill in the blank with suitable word :
Power is the rate of doing ___________.

Fill in the blanks with suitable words :
One watt is a rate of working of one ___________ per ___________.

A trolley is pushed along a road with a force of 400 N through a distance of 60 m in 1 minute. Calculate the power developed.

A man weighing 500 N carried a load of 100 N up a flight of stairs 4 m high in 5 seconds. What is the power?

An electric heater uses 600 kJ of electrical energy in 5 minutes. Calculate its power rating.