Tag: moving things around us

Questions Related to 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


Correct Option: A
Explanation:

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

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


Correct Option: B

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


Correct Option: A

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=$at^{2}$


Correct Option: A
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

The pendulum of a wall clock exhibits

  1. Rotatory motion

  2. Circular motion

  3. Linear motion

  4. Oscillatory motion


Correct Option: A

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


Correct Option: A
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.

 

A platform is moving in upward direction with uniform velocity 40 ${ ms }^{ -1 }$. When it reaches at a height of 100 m from the ground, a pocket is dropped  from it. The total distance traveled by pocket during its free fall is (Take $g=10{ ms }^{ -2 }$) 

  1. 160 m

  2. 260 m

  3. 180 m

  4. 300 m


Correct Option: C

What does the odometer of an automobile measure?

  1. Speed

  2. Distance

  3. Acceleration

  4. All


Correct Option: B
Explanation:

An odometer or odograph is an instrument that indicates distance traveled by the automobile

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. $\displaystyle \frac{ct}{2}$


Correct Option: D
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 $distance=speed*time=c*\dfrac{t}{2}$

Distance is a vector quantity. State whether true or false.

  1. True

  2. False


Correct Option: B
Explanation:

Distance is a scalar quantity. So the given statement is false.