English Medium Class 9 - CBSE Question Bank Solutions for Science

Why do we keep both snake and turtle in the same class?

According to the third law of motion, action and reaction

Calculate the average density of the earth in terms of g, G and R

A cube of side 5 cm is immersed in water and then in a saturated salt solution. In which case will it experience a greater buoyant force. If each side of the cube is reduced to 4 cm and then immersed in water, what will be the effect on the buoyant force experienced by the cube as compared to the first case for water. Give a reason for each case.

A ball weighing 4 kg of density 4000 kg m^–3 is completely immersed in water of density 103 kg m^–3 Find the force of buoyancy on it. (Given g = 10 m s^–2)

How is the power related to the speed at which a body can be lifted? How many kilograms will a man working at the power of 100 W, be able to lift at a constant speed of 1 m s^–1 vertically? (g = 10 m s^–2)

Draw a sketch of Bohr’s model of an atom with three shells.

Describe Bohr’s model of the atom.

Compare all the proposed models of an atom given in this chapter.

What are the functions of areolar tissue?

Name the tissue that connects muscle to bone in humans.

Name the tissue that stores fat in our body.

Name the connective tissue with a fluid matrix.

Identify the type of tissue in the bone.

A bus starting from rest moves with a uniform acceleration of 0.1 m s^-2 for 2 minutes. Find

1. the speed acquired
2. the distance travelled.

A train is travelling at a speed of 90 km h⁻¹. Brakes are applied so as to produce a uniform acceleration of −0.5 m s⁻². Find how far the train will go before it is brought to rest.

A motorboat starting from rest on a lake accelerates in a straight line at a constant rate of 3.0 m s⁻² for 8.0 s. How far does the boat travel during this time?

From a rifle of mass 4 kg, a bullet of mass 50 g is fired with an initial velocity of 35 m s⁻¹. Calculate the initial recoil velocity of the rifle.

Two objects of masses 100 g and 200 g are moving along the same line and direction with velocities of 2 m s⁻¹ and 1 m s⁻¹, respectively. They collide and after the collision, the first object moves at a velocity of 1.67 m s⁻¹. Determine the velocity of the second object.

Two objects, each of mass 1.5 kg are moving in the same straight line but in opposite directions. The velocity of each object is 2.5 m s⁻¹ before the collision during which they stick together. What will be the velocity of the combined object after collision?