JEE PHYSICS MCQ: MOTION IN PLANE

1 Hard

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Analyzing +4 | -1

Statement I Two forces (P+Q) and (P-Q) where

P \bot Q

, when act at an angle

{\theta _1}

to each other, the magnitude of their resultant is

\sqrt {3({P^2} + {Q^2})} ,

when they act at an angle

{\theta _2},

the magnitude of their resultant becomes

\sqrt {2({P^2} + {Q^2})}

. This is possible only when

{\theta _1} < {\theta _2}.

Statement II In the situation given above.

{\theta _1} = {60^ \circ }\,\,\mathrm{and}\,\,{\theta _2} = {90^ \circ }

In the light of the above statements, choose the most appropriate answer from the options given below.

View answer and explanation

Correct option: B

Both Statement I and Statement II are true

Option B (Both Statement I and Statement II are true) is correct because solving the equations for the resultant forces with the given angles confirms that both statements are true.

More Questions from MOTION IN PLANE

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Given,

\mathrm{\vec P} = \mathrm{\vec A} + \mathrm{\vec B}\,\,\mathrm{and}\,P = A + B.

The angle between

\mathrm{\vec A}\,and\,\mathrm{\vec B}

is Assertion: The necessary condition for motion in two dimensions, velocity and acceleration vectors should have any angle between

0^{\circ}

and

90^{\circ}

between them.
Reason: For two-dimensional or three-dimensional motion, velocity and acceleration of an object works in opposite direction.

\mathrm{If}\,(\mathbf{a}+3 \mathbf{b}) \cdot(7 \mathbf{a}-5 \mathbf{b})=0

and

(\mathbf{a}-4 \mathbf{b}) \cdot(7 \mathbf{a}-2 \mathbf{b})=0

. Then, the angle between

\mathbf{a}

and

\mathbf{b}

is At the top of the trajectory of a projectile, the direction of its velocity and acceleration are A ball is thrown at an angle

\theta

and another ball is thrown at an angle

\left(90^{\circ}-\theta\right)

with the horizontal direction from the same point with velocity

39.2 \mathrm{~ms}^{-1}

. The second ball reaches

50 \mathrm{~m}

higher than the first ball. Find their individual heights. Take

{g}=9.8 \mathrm{~ms}^{-2}

. Assertion: The drover in a vehicle moving with a constant speed on a straight road is in a non-inertial frame of reference.

Reason: A reference frame in which Newton's laws of motion are applicable is non-inertial.