Tag: physics

Questions Related to physics

Two bodies $A$ and $B$ having mass $M$ and $m$ respectively possesses same kinetic energy. Given that $M> m$. If ${\rho} _{A}$ and ${\rho} _{B}$ be their momentum, then which of the following statements is true?

  1. ${ \rho } _{ A }={ \rho } _{ B }$

  2. ${ \rho } _{ A }> { \rho } _{ B }$

  3. ${ \rho } _{ A }< { \rho } _{ B }$

  4. It cannot be predicted


Correct Option: C
Explanation:
Two bodies A and B having mass m and M respectively possesses same Kinetic energy : 
$K _A = K _B$
In general kinetic energy, $K = \dfrac{1}{2} mv^2 = \dfrac{p^2}{2m}$ where $p$ is momentum. 
$\therefore \dfrac{\rho _A ^2}{2M} = \dfrac{\rho _B ^2}{2m}$
$ \dfrac{\rho _A ^2}{M} = \dfrac{\rho _B ^2}{m}$
But $M>m$ and therefore for above equation to be true $\rho _A ^2 < \rho _B ^2$ or $\rho _A < \rho _B $ 

For constant non zero mass, momentum versus velocity graph is a:

  1. straight line parallel to x- axis

  2. straight line parallel to y- axis

  3. straight line passing through origin

  4. straight line passing through y- axis with an intercept


Correct Option: C
Explanation:

We know that,
Momentum = mass $ \times $ velocity
So, we know that when a graph is plotted, momentum against velocity, it is a straight line passing through the origin because momentum varies linearly with respect to velocity.

A body of mass $2 kg$ is sliding with a constant velocity of $4 m/s$ on a frictionless horizontal table. The net force required to keep the body moving with the same velocity is

  1. $8 N$

  2. $0 N$

  3. $4 N$

  4. $\dfrac { 1 }{ 2 }  N$


Correct Option: B
Explanation:

According to newton's first law of motion, an object either remains at rest or continues to move at a constant velocity, unless acted upon by an external net force.
Therefore 
The force required to keep the body moving with the same velocity is zero.

In a physical balance, when the beam is released with empty pans, the successive left and right turning points are obtained as 5; 6, 6 and 18, 18 respectively. After placing the substance whose mass is to be determined and when beam is released, the resting point obtained is 13. When 10 mg is added to the pan, the resting point is obtained as 11. If the mass at LRP is 60 g, the correct mass of the body corrected to a milligram is ______ g. 

  1. 59.996

  2. 56.5

  3. 59.99

  4. 56.599


Correct Option: A

State whether true or false.
The pointer of a spring balance will read zero when there is no load on the pan.

  1. True

  2. False


Correct Option: A
Explanation:

If no lead is applied to the spring balance, there will be no extension in the spring and hence the pointer will read zero in the spring balance. Thus the given statement is true.

The weight placed on the pan is a balance when HRP is obtained is 47.86 g. The difference between ZRP and HRP of the physical balance is 3. When 10 mg is added in its pan, the difference between HRP and LRP is obtained as 5. Determine the most accurate mass of the body.

  1. 478.672 g

  2. 34.73 g

  3. 47.866 g

  4. 47.532 g


Correct Option: C

A beam balance is used to measure the ________ of a body.

  1. weight

  2. mass

  3. force

  4. shape


Correct Option: B
Explanation:

A beam balance is used to measure the mass of the body precisely.

A knob at the baseboard can be used to raise or lower the _____of the physical balance

  1. beam

  2. weight 

  3. mass

  4. none


Correct Option: A

A spring balance gives the measure of the mass of a body. True or false.

  1. True

  2. False


Correct Option: B
Explanation:

Spring balance gives the measure of the weight of the body. Thus the given statement is false.

Point out the odd one out of the following
beam balance, spring balance,  physical balance 

  1. Spring balance

  2. Beam Balance

  3. Physical Balance

  4. None


Correct Option: A
Explanation:

Spring Balance is used to measure weight others used to measure mass