Chapter–4: Motion in a Plane Assertion Reason
These questions of two statements each, printed as Assertion and Reason. While answering these Questions you are required to choose any one of the following four responses.
(A) If both Assertion & Reason are true & the Reason is a correct explanation of the Assertion.
(B) If both Assertion and Reason are true but Reason is not a correct explanation of the Assertion.
(C) If Assertion is true but the Reason is false.
(D) If Assertion & Reason both are false.
Q.1 Assertion : The path of one projectile as seen from another projectile is a straight line.
Reason : Two projectiles projected at angles a and 90° – a have same range .
(1) A (2) B (3) C (4) D
Answer: 2
Q.2 Assertion : In case of projectile motion acceleration, horizontal component of velocity and mechanical energy remains unchanged but speed, vertical component of velocity, momentum, K.E. and P.E. change.
Reason : In the presence of air resistance, the range and maximum height attained reduce, but time of flight increases.
(1) A (2) B (3) C (4) D
Answer: 2
Q.3 Assertion : A body dropped from a given height and another body projected horizontally from the same height strike the ground simultaneously.
Reason : Because horizontal velocity has no effect in the vertical direction.
(1) A (2) B (3) C (4) D
Answer: 1
Q.4 Assertion : A projectile is thrown with an initial velocity of m/sec. If range of projectile is maximum then a = b.
Reason : In projectile motion, angle of projection is equal to 45° for maximum range condition.
(1) A (2) B (3) C (4) D
Answer: 1
Q.5 Assertion : In projectile motion the projectile hits the ground with the same velocity with which it was thrown.
Reason : In projectile motion horizontal velocity remains same but vertical velocity continuously change and particle strikes the ground with same vertical velocity with which the particle was thrown in vertical direction.
(1) A (2) B (3) C (4) D
Answer: 4
Q.6 Assertion : In projectile motion the vertical velocity of the particle is continuously decreased during its ascending motion .
Reason : In projectile motion downward constant acceleration is present in vertical direction.
(1) A (2) B (3) C (4) D
Answer: 1
Q.7 Assertion : In the projectile motion projected body behave just like a freely falling body.
Reason : There is no change in linear momentum in projectile motion.
(1) A (2) B (3) C (4) D
Answer:3
Q.8 Assertion : Projectile motion is uniformly accelerated motion. (Neglect the effect of air)
Reason : In projectile motion, speed remains constant.
(1) A (2) B (3) C (4) D
Answer: 3
Q.9 Assertion : Horizontal range is same for angle of projection q and (90 – q) if speed of projection is same.
Reason : Horizontal range is independent of angle of projection.
(1) A (2) B (3) C (4) D
Answer: 3
Q.10 Assertion : If the position vector of a particle moving in space is given by , then the particle moves along a parabolic trajectory.
Reason : Because and Þ y = – x2
(1) A (2) B (3) C (4) D
Answer: 1
Q.11 Assertion : In projectile motion, when horizontal range is n times the maximum height, the angle of projection is given by tan q =
Reason : In the case of horizontal projection the vertical velocity increases with time.
(1) A (2) B (3) C (4) D
Answer: 2
Q.12 Assertion : Path of projected ball becomes parabolic in gravitational field (q ¹ 90°).
Reason : Gravitational force always act perpendicular to velocity during the motion.
(1) A (2) B (3) C (4) D
Answer: 3
Q.13 Assertion : In projectile motion, the acceleration is constant in both magnitude and direction but the velocity changes in both magnitude and direction.
Reason : When a force or acceleration is acting in an oblique direction to the direction of velocity then both magnitude and direction of the velocity may be changed.
(1) A (2) B (3) C (4) D
Answer: 1
Chapter–3: Motion in a Straight Line Assertion Reason
Chapter–5: Laws of Motion Assertion Reason
