# NCERT Physics Class 11 Exemplar Ch 4 Motion in A Plane Part 1

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1 The angle between and is

(a)

(b)

(c)

(d)

Ans: (b)

2 Which one of the following statements is true?

(a) A scalar quantity is the one that is conserved in a process.

(b) A scalar quantity is the one that can never take negative values.

(c) A scalar quantity is the one that does not vary from one point to another in space.

(d) A scalar quantity has the same value for observers with different orientations of the axes.

Ans: (d)

3 Figure 1 shows the orientation of two vectors u and v in the XY plane.

If and

Which of the following is correct?

(a) a and p are positive while b and q are negative.

(b) a, p and b are positive while q is negative.

(c) a, q and b are positive while p is negative.

(d) a, b, p and q are all positive.

Ans: (b)

4 The component of a vector r along X-axis will have maximum value if

(a) r is along positive Y-axis

(b) r is along positive X -axis

(c)r makes an angle of with the X -axis

(d) r is along negative Y-axis

Ans: (b)

5 The horizontal range of a projectile fired at an angle of is 50 m. If it is fired with the same speed at an angle of its range will be

(a)

(b)

(c)

(d)

Ans: (c)

6 Consider the quantities, pressure, power, energy, impulse, gravitational potential, electrical charge, temperature, area. Out of these, the only vector quantities are

(a) Impulse, pressure and area

(b) Impulse and area

(c) Area and gravitational potential

(d) Impulse and pressure

Ans: (b)

7 In a two dimensional motion, instantaneous speed is a positive constant. Then which of the following are necessarily true?

(a) The average velocity is not zero at any time.

(b) Average acceleration must always vanish.

(c) Displacements in equal time intervals are equal.

(d) Equal path lengths are traversed in equal intervals.

Ans: (d)

8 In a two dimensional motion, instantaneous speed is a positive constant. Then which of the following are necessarily true?

(a) The acceleration of the particle is zero.

(b) The acceleration of the particle is bounded.

(c) The acceleration of the particle is necessarily in the plane of motion.

(d) The particle must be undergoing a uniform circular motion

Ans: (c)

9 Three vectors A, B and C add up to zero. Find which is false.

(a) is not zero unless B, C are parallel

(b) is not zero unless B, C are parallel

(c) If A, B, C define a plane, is in that plane

(d)

Ans: (c)

10 It is found that this necessarily implies,

(a)

(b) A,B are antiparallel

(c) A,B are perpendicular

(d)

Ans: (b)