Tag: motion around us

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Questions Related to motion around us

Multiple choice physics kinematics motion around us motion and rest moving things around us

If a body does not change its position with respect to its surroundings, the body is said to be at rest.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The body when considered in frame of reference of surroundings, then zero relative velocity means it is at rest. So. statement is true.

Multiple choice physics kinematics motion around us motion and rest moving things around us

In which of the following cases , the net force is zero?
I) A ball freely falling from a certain height
II) A cork floating on the surface of water
III) An object floating in air

  1. I and II only

  2. II and III only

  3. III and I only

  4. I, II and III
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A freely falling object has a net force equal to its weight (gravity), so it is not zero. A cork floating on water and an object floating in air (like a balloon) are in equilibrium where the upward buoyant force equals the downward gravitational force, resulting in a net force of zero.

Multiple choice physics kinematics motion around us motion and rest moving things around us

In the state of equilibrium
I) Net force is zero
II) Body at rest will continue to be in its state of rest
III) Body moving with uniform velocity will continue to be in its state of uniform velocity
IV) Body with linear momentum $\vec{p}$ will continue to have the same momentum $\vec{p}$.

  1. all are correct

  2. I, II, III are correct

  3. II, III, IV are correct

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In a state of equilibrium, the net force is zero, which implies no acceleration. By Newton's first law, an object at rest stays at rest, and an object in uniform motion continues at that velocity (constant momentum), making all statements correct.

Multiple choice physics kinematics motion around us motion and rest moving things around us

At the starts of a motion along a line the initial velocity is u and acceleration is at. The final velocity v is 

  1. v=u+at

  2. v=u+$at^{2}$

  3. $v=u+\frac{1}{2}at^{2}$

  4. v=$at^{2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let us assume a body that has a mass “m” and initial velocity “u”. Let after time “t” its final velocity becomes “v” due to uniform acceleration “a”. Now we know that:

Acceleration = Change in velocity/Time Taken

Therefore,  Acceleration = (Final Velocity-Initial Velocity) / Time Taken

Hence, a = v-u /t or at = v-u

Therefore, we have: v = u + at

Multiple choice physics kinematics motion around us motion and rest moving things around us

Symmetry of the laws of nature with respect to translation in time give rise to

  1. Conservation of linear momentum

  2. Conservation of angular momentum

  3. Conservation of cahrge

  4. Conservation of energy
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Time translation symmetry gives rise to the conservation of energy.

Space translation symmetry gives rise to conservation of momentum.

Rotational symmetry gives rise to conservation of angular momentum.

The conservation law associated with this symmetry is the conservation of electrical charge.

 

Multiple choice physics motion and measurement of distances motion around us motion and rest moving things around us

A laser signal sent towards the moon returns after t seconds.If c is speed of light, then the distance of the moon from the observer is

  1. ct

  2. $ct^{-1}$

  3. $ct^{-2}$

  4. $\displaystyle \frac{ct}{2}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A laser signal sent towards the moon returns after t seconds.

Time taken to reach moon is $\dfrac{time}{2}=\dfrac{t}{2}$
Therefore $distance=speed*time=c*\dfrac{t}{2}$