What is force? - class-VII
A comprehensive quiz covering force concepts including definitions, types of forces, effects of force, Newton's laws of motion, force units, and practical applications for 7th grade physics.
Questions
A force of N acts on a body of $5kg$ mass. Find the acceleration of body?
- $a=\dfrac{N}{50} m/{s}^{2}$
- $a=\dfrac{N}{15} m/{s}^{2}$
- $a=\dfrac{N}{5} m/{s}^{2}$
- $a=\dfrac{N}{10} m/{s}^{2}$
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
- Upper thread break first
- Lower thread break first
- Both will break at same time
- None of these two threads will break
Fill in the blanks .
At least _____________ object must interact for a force to come into play.
- 1
- 2
- 3
- 4
Which one of the following statements regarding Newton's first law of motion is incorrect?
- It is an independent statement
- it defines an inertial frame of reference
- It was first enunciated by Galileo
- It is a special case of Newton's second law.
Which statement defines force?
- 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
- When a force acts on a body that is free to move, the force is the rate of change of momentum of the body
- 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
- 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
Force exerted is :
- Effort
- Load
- Fulcrum
- None of these
You can increase the amount of force applied on a body by repeatedly:
- pushing it
- pulling it
- dragging it
- any or all of the above
A force cannot be seen but the effect of force can be felt.
- True
- False
- Ambiguous
- Data insufficient
Which of the following class of forces is different from others?
- Pulling of a cart
- Stretching of a coiled spring
- Kicking of a football
- Weight of the body
1 dyne is equal to
- 980 g wt
- $\displaystyle\ \frac { 1 }{ 980 } \ gwt$
- 980 kg wt
- None of these
Identify the action involved when a north pole of magnet brought near another north pole of magnet it repels?
- Pushing
- Throwing
- Pulling
- Lifting
Identify the type of force involved when loaded cart is moved.
- Lifting
- Pulling
- Running
- Reading
Which of the following actions can be grouped as push?
- Only a
- Only a and b
- only b and c
- a, b and c
Identify the action that can cause motion of a book placed on a table.
- Pulling
- Pushing
- Lifting
- All of the above
Which of the following actions can be grouped as pull:
- Only a
- a and b
- b and c
- a and c
Fill in the blanks:
- pressure
- attraction
- force
- repulsion
Identify the action involved in opening or shutting a door.
- Pulling
- Pushing
- Both a and b
- None of the above
Identify the action involved when a magnet attracts a piece of iron towards it.
- Pushing
- Pulling
- Flying
- Picking
Fill in the blanks:
- pressure
- attraction
- repulsion
- force
- objects interact.
- objects do not interact.
- object move.
- None of these
In which of the following cases, a force is not being applied?
- A man standing behind a stationary car.
- A car being pushed by a man.
- A man trying to stop a sliding car.
- A man standing on a car.
- Magnetic force
- Contact force
- Non-contact force
- Muscular force
What happens when there is no interaction between the objects?
- Force comes in action.
- Force does not come in action.
- Force may or may not come in action.
- None of the above is correct
A force acts between two bodies if:
- both the bodies are pushing each other.
- both the bodies are pulling each other.
- either of the two bodies are pushing or pulling the other body.
- all of these
Fill in the blanks:
- force is applied due to interaction.
- force is not applied although there is interaction.
- force is applied although there is an interaction.
- none of the above.
A force when applied on a non rigid object
- Does not change the inter spacing between its constituent particles
- Do not cause any change in its dimension
- Do not produce motion in it
- None
When a force is applied on a rigid object
- It changes the inter spacing between its constituent particles.
- It changes the dimension of the object
- It only causes motion in it
- All
If two bodies do not interact
- still a force can be applied
- no force can be applied
- contact force can be applied
- non-contact force can be applied
Mark the incorrect option:
- A force always make an object to move
- A force has both magnitude and direction
- A force can be represented by an arrow
- Force is a vector quantity
Fill in the blank.
- Shape
- Size
- Direction of force
- Both a and b
When a spring is pulled :
- shape of the spring changes
- size of the spring changes
- size of the spring doesn't change
- both a and b
Mark the correct option
- Force can be seen
- When an inflated balloon is pressed between the two hands,only its shape changes
- Force is a push,pull or squeeze
- All
As longer the interaction between two objects exist
- The force remains
- The force stops after the initial interaction
- Both a and b
- The force remains for a specific time interval
Mark the correct option
- A force can make stationary object move.
- A force can stop a moving object
- A force can increase the speed of a moving object
- All
Fill in the blank.
- Itself
- Another object
- Both
- May itself and may be another object
Which of the following is/are correct
- At least two objects must interact for a force to come into play.
- Interaction of one object with another object results in a force between the two objects.
- Interacting forces may be push or pull
- All
A force between two objects come into play when
- Both objects are very heavy
- Both objects move with some speed
- Both objects interact with each other
- All
Pulling of a cart/tram is an example of
- Resultant force
- Gravitational force
- Contact force
- Action at a distance force
Suppose a man is standing behind a stationary car.Which of the following options will be correct?
- The car will start moving towards the man
- The car will start moving away from the man
- The car will not move at all
- None
This S.I. unit of force is____
- Joules
- Newton
- Watt
- Dyne
A ball of mass $400 \ gm$ is dropped from a height of $5 \ m$. A boy on the ground hits the ball vertically upwards with a bat with an average force of $100 N$ so that it attains a vertical height of $20 \ m$. Find the time for which the ball remains in contact with the bat.
- $0.12 s$
- $0.24 s$
- $0.36 s$
- $0.48 s$
Swimming is based on Newton's:
- First law of motion
- second law of motion
- third law of motion
- law of gravitation
If force $\vec {F} = 5\hat {i} + 3\hat {kj} + 4\hat {k}$ makes a displacement of $\vec {s} = 6\hat {i} - 5\hat {k}$, work done by the force is
- $10\ unit$
- $122\sqrt {5}\ unit$
- $5\sqrt {122}\ unit$
- $20\ unit$
If the interatomic spacing in a steel wire is ${ 2.8\times 10 }^{ -10 }$ m. and ${ Y } _{ steal }=2\times 10^{ 11 }N/m^{ 2 }$,then force constant in N/m is-
- 5.6
- 56
- 0.56
- 560
- True
- False
If in a system of forces acting on a rigid body R.G $\neq $ 0, then the given system of forces is equivalent to
- degenerate wrench
- non-degenerate wrench
- a couple
- a single force
State whether true or False
10 mN is equal to $10^{-3}$ dynes.
- True
- False
Which of the following laws represents the qualitative measure of force?
- Newton's first law of motion
- Fleming's right hand rule
- Fleming's left hand rule
- Zeroth law of thermodynamics
The state of rest or state of motion of a body can be changed by using
- Pressure
- Force
- Heat
- None of these