Tag: physics

Questions Related to physics

A set of unequal and opposite forces is called:

physics force concept of force and its unit force - push or pull forces

  1. Balanced forces

  2. Unbalanced forces

  3. Equilibrium forces

  4. None

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Correct Option: B
Explanation:

Unequal and opposite forces do not cancel out each other completely and thus resulting in net force acting in a particular direction. A set of such forces is called a set of unbalanced forces.

A number of forces act on a body at the same point and the body does not move. What do you conclude from this?

physics force concept of force and its unit force - push or pull forces

  1. Body is acted upon by a set of balanced forces.

  2. Body is acted upon by a set of unbalanced forces.

  3. Body is acted upon by a set of unknown forces.

  4. None of the above

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Correct Option: A
Explanation:

Balanced forces cancel out the effect of each other. Thus, no net external force acts on the body and hence a body at rest does not move.

If the forces on an object are balanced, then the net force is:

physics force concept of force and its unit force - push or pull forces

  1. Either positive or negative depending on the strength of forces.

  2. Negative

  3. Positive

  4. Zero

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Correct Option: D
Explanation:

If the forces on the object are balanced, this means that the individual force cancel out each other resulting in a zero net force acting on the object.

The strength of force is expressed by?

physics force concept of force and its unit force - push or pull forces

  1. Direction

  2. Magnitude

  3. Both

  4. None

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Correct Option: B
Explanation:

Force could be larger or smaller than the other.the strength of a force is usually expressed by its magnitude.

Mark the correct statement(s).

physics force concept of force and its unit force - push or pull forces

  1. When unbalanced forces act on an object at rest, the object will move.

  2. Unbalanced forces are necessary to cause a non-moving object to start moving.

  3. Unbalanced forces produces change in motion (acceleration).

  4. All

Show answer
Correct Option: D
Explanation:

Unbalanced forces result in a non-zero net external force acting on a body which produces an acceleration of the body in a particular direction and hence the body at rest starts to move in that direction. Thus unbalanced forces are necessary to cause a non moving object to start moving. Thus option D is correct.

You alone can push a roller. But when your friend joins you, the roller moves faster. This is because:

physics force concept of force and its unit force - push or pull forces

  1. forces in same direction add up.

  2. forces in same direction do not add up.

  3. forces in same direction get subtracted.

  4. forces in same direction remain same.

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Correct Option: A
Explanation:

When your friend joins you, both of you push the roller in same direction. So, your forces, being applied in same direction, add up to a larger value. Thus the roller moves faster.

If force is applied on the body in the direction of motion then

physics force concept of force and its unit force - push or pull forces

  1. Speed of the body will increase

  2. Speed of the body will decrease

  3. Speed of the body will not change at all

  4. All the options are possible

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Correct Option: A
Explanation:

If applied force acts on a body in the direction of motion,the speed of the body will increase.

If the direction of force on the body is opposite to the direction of motion,the speed will decrease.

Which of the following pairs of forces will never give resultant force of $2N$

physics force concept of force and its unit force - push or pull forces

  1. $2N$ and $2N$

  2. $1N$ and $1N$

  3. $1N$ and $3N$

  4. None of these

Show answer
Correct Option: A
Explanation:
Because if these two forces Act then it cancelled out because they have the same value. Either it acts in same or opposite direction 

A particle is moving along x-axis under the action of a force, $F$ which varies with its postion (x) as $F \propto x^{-1/4}$. The variation of power due to this force with $x$ is

physics force concept of force and its unit force - push or pull forces

  1. $x^{\dfrac{1}{3}}$

  2. $x^{\dfrac{1}{8}}$

  3. $x^{\dfrac{1}{2}}$

  4. $x^{\dfrac{1}{4}}$

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Correct Option: D

A rope of mass $ 5 kg$ is moving vertically in vertical position with an upwards force of $100$ $N$ acting at the upper end and a downwords force of $70$$N$ acting at the lower end The tension at midpoint of the rope is

physics force concept of force and its unit force - push or pull forces

  1. $100 N$

  2. $85 N$

  3. $75 N$

  4. $105 N$

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Correct Option: B