Tag: force and newton's laws of motion

Questions Related to force and newton's laws of motion

Why athletes stop themselves before the line marked for javelin throw

physics force and newton's laws of motion concept of inertia galileo's law and inertia mass and inertia

  1. Due to inertia of rest

  2. Due to inertia of motion

  3. Due to inertia of direction

  4. All

Show answer
Correct Option: B
Explanation:

Due to inertia of motion, an object do not stop all of a sudden rather it continues to move over some distance. Hence the athletes stop themselves much before line marked so that they come to rest before crossing that line, otherwise it is said to be a foul.

The sparks produced during sharpening of a knife against a grinding wheel leaves the rim of the wheel tangentially. This is due to which of the following?

physics force and newton's laws of motion concept of inertia galileo's law and inertia mass and inertia

  1. Inertia of rest

  2. Inertia of motion

  3. Inertia of direction

  4. Force applied

Show answer
Correct Option: C
Explanation:

Just after the sparks are produced, the force acting on the sparks becomes zero and due to inertia of direction, they start to move in their initial direction of motion which is tangential to the rim of the grinding wheel.

When a bus starts suddenly, the person falls backwards because of

physics force and newton's laws of motion concept of inertia galileo's law and inertia mass and inertia

  1. Inertia of rest of the passenger

  2. Inertia of motion of the passenger

  3. Inertia of rest of the bus

  4. None of the above

Show answer
Correct Option: A
Explanation:

When a bus starts suddenly,the person falls backwards because of inertia of rest of passenger.This is due to the fact that because of their inertia ,the passengers tend to remain in their state of rest when the bus starts suddenly.

Which of the following statement is true when a magician pulls a tablecloth from under a table full of dishes without disturbing the dishes?

physics force and newton's laws of motion concept of inertia galileo's law and inertia mass and inertia

  1. Gravity holds the dishes still

  2. The weight of the dishes is reduced

  3. Action-reaction forces are in operation

  4. The dishes have inertia

  5. The dishes have no acceleration

Show answer
Correct Option: D
Explanation:

The dishes have the inertia at rest, thus they tend to remain at rest even when the tablecloth is pulled of suddenly from the table and hence the dishes do not get disturbed.

Suppose gravity of earth suddenly becomes zero, then in which direction
will the moon begin to move if no other celestial body affects it ?

physics force and newton's laws of motion concept of inertia galileo's law and inertia mass and inertia

  1. Radial

  2. Tangential

  3. cant say

  4. None

Show answer
Correct Option: B
Explanation:

Moon will be launched in tangential direction with a speed at which it was orbiting around the earth.

In other words, it's speed and direction will be what it was at the time when gravitational force of earth ceased to exist.

Passengers standing in a bus are thrown outwards when the bus takes a sudden turn. This is due to:

physics force and newton's laws of motion concept of inertia galileo's law and inertia mass and inertia

  1. outward pull on them

  2. inertia

  3. change in momentum

  4. change in acceleration

Show answer
Correct Option: B
Explanation:

Newton's I law of inertia states that an object will change its direction when a force is applied to it. Hence, when a bus takes a sudden turn the passengers are thrown outward. This is due to the inertia of direction.

A truck and a car are moving with same kinetic energy. They are brought to rest by the application of brakes which provide equal force.

physics force and newton's laws of motion concept of inertia galileo's law and inertia mass and inertia

  1. both will cover equal distance

  2. the truck will cover a greater distance

  3. the car will cover a greater distance

  4. none of the above

Show answer
Correct Option: B
Explanation:

We know that, ${u}^{2}=2as$    (as final velocity will be zero).

$\Rightarrow$ $s=m\dfrac{{u}^{2}}{2F}$.
truck has greater mass  so distance will be more for truck yhan the car.

Two balls of the same size but of different materials, rubber and iron are kept on the smooth floor of a moving train. The brakes are applied suddenly to stop the train. Will the balls start rolling? If so, in which direction? Will they move with the same speed? 

physics force and newton's laws of motion concept of inertia galileo's law and inertia mass and inertia

  1. Iron ball is faster than rubber ball

  2. Rubber ball is faster than iron ball

  3. Both move at the same speed

  4. None of them move

Show answer
Correct Option: B
Explanation:

(a) Inertia is the name for the tendency of an object in motion to remain in motion, or an object at rest to remain at rest, unless acted upon by a force. This concept was quantified in Newton's First Law of Motion. For example when a car is abruptly accelerated, drivers and passengers may feel as though their bodies are moving backward. In reality, inertia is making the body want to stay in place as the car moves forward.

(b) Yes, both the balls will start rolling due to inertia of motion. The train stops due to brakes. But the balls continue to move in the direction of the train. But the balls will not roll with the same speed. Iron ball will move slower than the rubber ball because it is heavier in weight.

The ratio of inertial force to viscous force represents

physics force and newton's laws of motion inertia and mass concept of inertia galileo's law and inertia

  1. Magnus effect

  2. Reynolds number

  3. Torricelli's law

  4. Relative density

Show answer
Correct Option: B
Explanation:

Reynolds number represents the ratio of inertial force to viscous force.

Inertia of a body has direct dependence on :

physics force and newton's laws of motion inertia and mass concept of inertia galileo's law and inertia

  1. Velocity

  2. Volume

  3. Mass

  4. Density

Show answer
Correct Option: C
Explanation:

Mass is called as transnational inertia of body.

More mass means more force is required to change its state.
So option C is correct.