Tag: concept of force and its unit

Questions Related to concept of force and its unit

A force of N acts on a body of $5kg$ mass. Find the acceleration of body? 

physics force and types of force introduction to force what is force? concept of force and its unit

  1. $a=\dfrac{N}{50} m/{s}^{2}$

  2. $a=\dfrac{N}{15} m/{s}^{2}$

  3. $a=\dfrac{N}{5} m/{s}^{2}$

  4. $a=\dfrac{N}{10} m/{s}^{2}$

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Correct Option: C
Explanation:

$F=ma$

$N=5a$
$\dfrac { N }{ 5 } =a$
$a=\dfrac{N}{5} m/{s}^{2}$

A stone is suspended by a thread from a rigid support, another thread of same quality is attached at the bottom of done if the lower thread is pulled suddenly then

physics force and types of force introduction to force what is force? concept of force and its unit

  1. Upper thread break first

  2. Lower thread break first

  3. Both will break at same time

  4. None of these two threads will break

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Correct Option: B

Fill in the blanks .
At least _____________ object must interact for a force to come into play. 

physics force and types of force introduction to force what is force? concept of force and its unit

  1. 1

  2. 2

  3. 3

  4. 4

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Correct Option: B
Explanation:

Forces are used in our daily life actions like pushing, pulling, lifting, twisting etc. So, a force is a pull or push acting on an object which tends to change the state of rest/ motion of an object. An interaction of one object with another object results in a force between the two objects.

For example, Weightlifter uses muscular force to lift the weights.

Hence, At least 2 object must interact for a force to come into play. 

Which one of the following statements regarding Newton's first law of motion is incorrect?

physics force and types of force introduction to force what is force? concept of force and its unit

  1. It is an independent statement

  2. it defines an inertial frame of reference

  3. It was first enunciated by Galileo

  4. It is a special case of Newton's second law.

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Correct Option: A

Which statement defines force?

physics force and types of force introduction to force what is force? concept of force and its unit

  1. When a force acts on a body that is free to move, the force is the product of the mass of the body and its acceleration

  2. When a force acts on a body that is free to move, the force is the rate of change of momentum of the body

  3. When a force acts on a body that is free to move, the force is the work done by the force divided by the distance moved by the body

  4. When a force acts on a lever and causes a moment, the force is the moment divided by the perpendicular distance of the force from the pivot

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Correct Option: B
Explanation:

we know that 

$F= ma $ ..........(1)
and $a = \dfrac{dv}{dt}$
So from above eqn . 
$\implies F = \dfrac{mdv}{dt}$
$\implies F = \dfrac{dmv}{dt}$
$\implies F = \dfrac{dp}{dt}$
So, force = rate of change of momentum

Force exerted is :

physics force and types of force introduction to force what is force? concept of force and its unit

  1. Effort

  2. Load

  3. Fulcrum

  4. None of these

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Correct Option: A
Explanation:

Effort is defined as a force exerted by a machine or in a process.

You can increase the amount of force applied on a body by repeatedly:

physics force and types of force introduction to force what is force? concept of force and its unit

  1. pushing it

  2. pulling it

  3. dragging it

  4. any or all of the above

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Correct Option: D
Explanation:

By repeatedly pushing, pulling or dragging a body, we can increase the amount of force applied on that body. Hence option D is correct.

A force cannot be seen but the effect of force can be felt.

physics force and types of force introduction to force what is force? concept of force and its unit

  1. True

  2. False

  3. Ambiguous

  4. Data insufficient

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Correct Option: A
Explanation:

According to Newton's first law, force is the rate of change of momentum.
Therefore, a force is not a physical object that can be seen. However, the effect of a force on an object can be seen (i.e its changing momentum)

Which of the following class of forces is different from others?

physics force and types of force introduction to force what is force? concept of force and its unit

  1. Pulling of a cart

  2. Stretching of a coiled spring

  3. Kicking of a football

  4. Weight of the body

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Correct Option: D
Explanation:

Pulling of a cart, stretching of a coiled spring and kicking of a ball take place due to contact forces but weight of the body (gravitational force) is a non-contact force.

Hence option D is correct.

1 dyne is equal to

physics force and types of force introduction to force what is force? concept of force and its unit

  1. 980 g wt

  2. $\displaystyle\ \frac { 1 }{ 980 } \ gwt$

  3. 980 kg wt

  4. None of these

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Correct Option: B
Explanation:

The weight of mass of 1 gram of body is

$ w = mg$
$ w = 1 gm \times980 cm/s^2= 980\  dyne $
So, $ 1\ dyne = \dfrac {1}{980} gwt $
gwt is weight equivalnet in grams.
$ Always\, g wt \times \, g = dyne$