Motion in a PlaneNEET Physics · Class 11 · NCERT Chapter 3

You can expect 2 to 4 questions from Motion in a Plane in NEET 2027. Projectile motion is the most heavily tested topic, followed by vector addition or resolution and uniform circular motion. The chapter has high PYQ frequency.

Yes. Motion in a Plane is the foundation for Laws of Motion, Work-Energy, Rotational Motion and even Electromagnetism. Vectors appear in almost every chapter that comes after this one. Master it early.

For a projectile launched at angle theta with initial speed u: time of flight T = 2u sin theta / g, maximum height H = u squared sin squared theta / (2g), range R = u squared sin 2 theta / g. The trajectory is a parabola: y = x tan theta minus g x squared / (2 u squared cos squared theta).

Range is u squared sin 2 theta / g. The function sin 2 theta has the property sin 2 theta = sin (180 minus 2 theta), which means angles theta and (90 minus theta) give the same range. So 30 degrees and 60 degrees produce the same range, just different times of flight and heights.

Centripetal acceleration is directed toward the centre of the circle and changes the direction of velocity, not its magnitude. It equals v squared / r. Tangential acceleration is along the velocity vector and changes the speed. In uniform circular motion, only centripetal acceleration is present; tangential acceleration is zero.

Dot product gives a scalar: A dot B = A B cos theta. It is used for work (force dot displacement) and angle between vectors. Cross product gives a vector: A cross B = A B sin theta n hat, perpendicular to both. It is used for torque (r cross F) and angular momentum.

Resolve each vector into x and y components. Add the x-components to get Rx and the y-components to get Ry. The magnitude of the resultant is square root of (Rx squared plus Ry squared) and its direction is given by tan inverse (Ry over Rx). The component method is faster than the parallelogram method for most NEET problems.