Frictional Force

Q. When we apply brakes in bicycles, which force stops the wheels?

1. Frictional force
2. Gravitational force
3. Magnetic force
4. Normal force

Q. Friction is such a force that slows down or stops a moving body as it opposes___.

1. rapid motion
2. relative motion
3. any motion
4. slow motion

Q.

The increase in the speed of a car is proportional to the additional petrol put into the engine .Is it possible to accelerate a car without putting more or less petrol in to the engine

Q. When a stationary object is placed on another stationary object, there will be no friction acting between the two stationary objects.

1. True
2. False

Q. In absence of any other forces, moving bodies will not stop moving without friction.

1. True
2. False

Q.

Which of the following statement about the Motion is correct?

1. The motion of an object is only relative to the position of another object.

2. Motion is the change of location or position of an object with respect to time and some point of reference.

3. All of these.

4. Change in motion is the result of an applied force.

Q.

A stone of mass 1 kg is thrown with a velocity of 20 m/s across the frozen surface of a lake. It comes to rest after travelling a distance of 50 m. What is the force of friction between the stone and the ice?

1. 3N

2. There is no friction between stone and ice

3. 4N

4. 5N

Q.

What happens if there no friction exists?

Q. Air offers friction to a moving body.

1. True
2. False

Q. To start motion in an object kept on a surface, we need to apply a force which is ___ the maximum frictional force offered by the surface to the object.

1. equal to
2. less than
3. more than
4. slightly less than

Q. On application of an external force on box A, the direction of frictional force on box A, applied by box B, would be:

1. towards the applied force
2. downwards
3. upwards
4. opposite to the direction of the applied force

Q. Friction is ____.

1. a non-contact force
2. a field force
3. a surface force
4. an electrical force

Q.

Why do we have to replace parts of machine time to time?

Q. A person is balancing between two walls. Identify the direction of friction at the point of contact

1. 
2. 
3. 
4. 

Q. what is galileo experiment and what is the result of this experiment?

Q. Efficiency of machines with movable parts is low because due to friction a lot of energy is lost in the moving parts.

1. False
2. True

Q.

When a fast moving vehicle is suddenly stopped by applying the brakes, the force that causes deceleration is exerted by the brakes.

1. Because action and reaction pair are never equal

2. Due to opposing force of friction

Q. A small steel ball is released from rest at the rim of a hemispherical glass bowl as shown below. Considering no friction, choose the correct statement.

1. The ball will move out of the glass bowl on reaching point B.
2. The ball will stop at point C after a number of to-and-fro motions.
3. The ball will keep oscillating between points A and B and will never stop.
4. The ball will not move at all since friction is necessary for motion.

Q.

What are aerodynamic clothes and where these clothes are used?

Q. According to , any object moving will come to rest on its own without any external force.

1. Aristotle
2. Galileo
3. Einstein
4. Newton

Q.

According to_____ , any object in motion will continue to be in motion unless it is stopped by a/an_______ force.

1. Galileo
2. Aristotle
3. natural
4. external

Q. Friction is a/an force.

1. imaginary
2. non-contact
3. contact
4. internal

Q.

Which of the following forces is necessary for horizontal motion on the ground?

1. Normal force

2. Weight

3. Friction

4. We can walk without any force

Q.

In which of the following options is the frictional force working?

1. A boulder rolling down a mountain

2. Airplane flying

3. A swimmer in river

4. None of these

Q. Define moment of a force

Q. State whether the given statement is true or false :

1. True
2. False

Q. Consider the given scenario wherein the bus, the auto, the car and the motorcycle are moving with the same speed.

Then choose the incorrect statement: $\left[1\text{mark}\right]$

A. The auto is at rest with respect to the bus.
B. The bus is in motion with respect to the motorcycle.
C. The motorcycle is in motion with respect to the car.
D. The car is in motion with respect to the bus.

Q. A cylinder is pure rolling up an inclined plane. It stops momentarily and then rolls back. The force of friction:

1. on the cylinder is zero throughout the journey.
2. is directed opposite to the velocity of the centre of mass throughout the journey.
3. is directed up the plane throughout the journey.
4. is directed down the plane throughout the journey.

Q. Which of the following describe a frictional force?

1. Frictional force always opposes the state of motion of an object.
2. Frictional force is parallel to the surface in contact.
3. Frictional force always produces heat
4. Frictional force can be increased or reduced