Viscous Force

Q.

What is cohesive force?

Q.

Two forces each of magnitude 2 N act vertically upward and downward respectively .on two ends of a uniform rod of length 1m, freely pivoted at its center. determine the resultant moment of forces about the midpoint of the rod.

Q.

A boat carrying steel balls is floating on the surface of water in a tank. If the balls are thrown into the tank one by one , how will it affect the level of water?

Q.

Which of the following factors affect the viscosity of a liquid?

1. Density

2. Surface tension

3. Temperature

4. None of these

Q.

The resistance offered by a liquid to its flow is called

1. Viscosity

2. None of these

3. Surface tension

4. Buoyancy

Q.

State the factors on which upthrust or buoyant force depends?

Q.

Which of the following liquids is the most viscous?

1. Alcohol

2. Honey

3. Water

4. Kerosine

Q.

Frictional force between layers of flowing fluid is known as

1. Gravity.

2. Viscosity.

3. Surface tension.

4. None of these.

Q. Swimming is possible due to

1. Galileo’s law of inertia
2. Newton’s second law of motion
3. Newton’s third law of motion
4. Newton’s first law of motion

Q. A wooden block is placed on a table top. Name the forces acting on the block and draw neat and labelled diagrams to show the point of application and direction of these forces.

Q.

With increase in temperature, viscosity of lubricating oil

1. first increases and then decreases

2. decreases

3. increases

4. remains constant

Q.

Is a satellite moving around the Earth in a circular orbit accelerated? Explain.

Q. A block of mass 2 kg placed on a rough horizontal surface having coefficient of friction 0.25 is acted upon by a force of
10 N as shown below. The distance travelled by the block in the first five seconds is

1. 16.75 m
2. 31.25 m
3. 62.5 m
4. Zero

Q.

Why does a swimmer push the water with his hands in the backward direction?

Q.

Is acceleration due to gravity a universal constant?

Q. Sort the following liquids in the increased order of the viscosity.

1. 
   Acetone
2. Honey
3. Resin
4. Water

Q.

Hydraulic press is based on the ________ law.

Q.

In the beam balance, when the beam is balanced horizontal position, then it is in _______ equilibrium.

Q. A ball is hanging by a string from the ceiling of the roof. Draw a neat labelled diagram showing the forces acting on the ball and the string.

Q. Why solubility of some gases like hydrogen or inert gases , increase with increase in temperature

Q. Archimedes' principle states that when an object is partially or fully immersed in a fluid, a force of buoyancy acts on it in the upward direction. This force is equal to _______________.

1. the weight of the fluid displaced by the body
2. the weight of the body
3. the volume of the body
4. the volume of the fluid displaced

Q.

A ball dropped in a liquid with some velocity will slow down due to which of the following forces?

1. Buoyant force

2. Viscous force

3. All of these

4. Surface tension

Q.

Explain why the angle of contact of mercury with glass is obtuse, while that of water with glass is acute.

Q.

State the laws of liquid pressure.

Q.

The friction within different fluid layers is known as___.

1. internal friction

2. laminar flow

3. turbulent flow

4. viscosity

Q. State the applications of Archimedes principle.

Q.

Rohan is pulling a trolley of mass 10 kg with a force of 25 N. The friction that can be applied by the floor on the trolley is 50 N. Calculate the push force applied by Rahul if the trolley is moving towards left with an acceleration of $0.5m/s^2$.

1. 35 N
2. 30 N
3. 40 N
4. 25 N

Q.

State two effects that a balanced force can produce in a non-rigid body fixed at a position.

Q. Two persons $P$ and $Q$ are flying in a helicopter horizontally at a constant speed. All of a sudden, $P$ falls down. During the fall of $P$, at any instant, $Q$ locates $P$:

1. Down, at an angle (acute) to the front of vertical

2. Whose position depends upon the speed of the helicopter
   
3. Down at an angle (acute) to the rear of vertical
   

4. Vertically down

Q.

What are Cohesive and Adhesive forces?