MARYGIRI SENIOR SECONDARY SCHOOL
SREEKANDAPURAM
UNIT- MOTION IN A PLANE
PHYSICS ASSIGNMENT
DOA: 13-07-2013
DOS: 18-07-2013
Class XI
1. Name two physical quantities which remain constant for a body in projectile motion.
2. A hunter aims at a monkey sitting on a distant tree. The monkey falls at the instant of firing of the gun.
Will the bullet hit the monkey? Justify your answer. Can you conclude that the magnitude of each
component of the vector is also doubled? Justify your answer.
3. The magnitude of the sum of two vectors is equal to the magnitude of the difference between them.
What is the angle between the two vectors?
4. The resultant of two forces of equal magnitude acting at right angles to each other is 1414 N. Find the
magnitude of each force.
5. A particle has displacement of 10 m towards east and 5 m toward the north and then 6m vertically
upward. Find the magnitude of the sum of these displacements.
6. Two forces of 10 N and 6 N act up on a body. The directions of the forces are unknown. The resultant
force on the body may lie between which limits?
7. Can three vectors which are not in one plane give a zero resultant? Justify.
8. What is the angle between the vectors iˆ  ˆj and iˆ  ˆj ? Represent them graphically and find their
magnitudes.
9. A wooden block of 1 kg rests on a smooth surface inclined 30o with the horizontal. Find the components
of the weight of the block perpendicular and parallel to the plane.
10. At what point on the path of a projectile is the acceleration perpendicular to the velocity?
11. A tennis ball is hit upward in to the air and moves along an arc. Neglecting air resistance, where along
the arc is the (i) KE is maximum (ii) PE is maximum (iii) KE is minimum (iv) momentum is minimum?
12. A bullet is dropped from a certain height and at the same time another bullet is fired horizontally from
the same height. Which one will hit the ground earlier and why?
13. A body is projected with a speed of 14.14 m/s at an angle to the horizontal to have maximum horizontal
range. What is the velocity at the highest point?
14. A cricketer can throw a ball to a maximum horizontal distance of 100 m. How much high above the
ground the cricketer can throw the above ball?
15. Can there be motion in two dimension with acceleration in one dimension? Support your answer.
16. Can a body accelerate if its speed is constant? Can it accelerate if its velocity is constant?
17. Both magnitude and direction of the acceleration of a body are constant. Will the path of the body
necessarily be a straight line?
18. A railway carriage moves over a straight track with acceleration a. A passenger in the carriage drops a
stone. What is the acceleration of the stone with respect to (i) the carriage and (ii) the earth?
19. A bomb is dropped from an air craft when it is directly above a target at a height of 1000 m. The air craft
is moving with a velocity of 500 km/h. Will the bomb hit the target? If not, by how much distance will the
bomb miss the target?
20. Calculate the angular velocity of a particle which makes 360 revolutions per minute. What is the linear
velocity if the radius is 4 cm?


21. Find the value of n such that A  4iˆ  nˆj  2kˆ is perpendicular to B  2iˆ  3 ˆj  kˆ .
22. Define the terms: (i) angular velocity (ii) time period and (iii) frequency in relation to uniform circular
motion. Give the relationship between these.
23. State with reason which of the following statements are true or false: (i) The net acceleration of a
particle in circular motion is always along the radius of the circle towards the centre. (ii) The acceleration
vector of a particle in uniform circular motion averaged over one cycle is a null vector. (iii) The velocity
vector of a particle at a point is always along the tangent to the path of the particle at that point.
24. Define (i) Scalar product and (ii) vector product of two vectors. Mention two properties of each. State
any rule to determine the direction of vector product.
25. What is meant by centripetal acceleration? Derive an expression for it in terms of constant speed of the
body.
Class XI Physics Assignment, October, 2012.
MARYGIRI SENIOR SECONDARY SCHOOL
SREEKANDAPURAM
UNIT- MOTION IN A PLANE
DOA: 13-07-2013
Class XI
DOS: 18-07-2013
1. A boat is sent across a river with a velocity of 8
10. An aeroplane is flying at a speed of 144 km/h
km/h. If the resultant velocity of the boat is 10
at an altitude of 1000 m. How far from a given
km/h, the river is flowing with a velocity of:
target should a bomb be released from it to hit
a) 12.8 km/h
b) 6 km/h
the target?
c) 8 km/h
d) 10 km/h
a) 571.43 m
b) 671.43 m
2. Find the value of c if A=0.4 i+0.3 j+c k is a unit
c) 471.43 m
d) 371.34 m
vector:
11. A cricket ball is hit at 45o to the horizontal with
a kinetic energy K. The kinetic energy at the
a) 0.5
b) 1.5
highest point is:
c) 0.75
d) 1
a) K
b) K/2
c) 2 K
d) zero
3. A bird is flying towards south with a velocity 40
12. An aeroplane is moving on a circular path with
km/h and a train is moving with a velocity of 40
a speed of 250 km/h. The change in velocity in
km/h towards east. What is the velocity of the
half revolution is:
bird w.r.t. an observer in train?
a) zero
b) 250 km/h
a) 40 2 km/h N-E b) 40 2 km/h S-E
c) 500 km/h
d) 250 2 km/h.
c) 40 2 km/h S-W d) 40 2 km/h NW
13. Two bodies are projected with angles θ and
4. Two forces each numerically equal to 5 N, are
(90 – θ) to the horizontal with same speed. The
acting as shown in figure. Then the resultant is:
ratio
of their horizontal ranges is:
a) 2.5 N
b) 5 N
o
a)
1
:
1
b) 1 : tan θ
60
c) tan θ : 1
d) 1 : cot θ
c) 5 3 N
d) 10 N
14.
The
ratio
of
the
maximum
heights in Q.No 13
5. A bus is moving on a straight road towards
is:
north with a uniform speed of 50 km/h then it
a) 1 : 1
b) 1 : tan θ
turns left through 90o. If the speed remains
2θ : 1
c)
tan
d) 1 : cot θ
unchanged after turning, the increase in the
15.
A
projectile
thrown
with
a velocity v at an angle
velocity of the bus in the turning process is:
θ
has
a
range
R
on
the
surface
of earth. For
a) 70.7 km/h along S-W direction
same v and θ, its range on the surface of moon
b) zero
will be:
c) 50 km/h along west
a) 36 R
b) R/36
c) 6 R
d) R/6
d) 70.7km/h along N-W direction.
16. The x and y coordinates of a particle at any
6. One of the rectangular components of velocity
time t are given by x = 2t+4t2 and y = 5t, where
of 60 km/h is 30 km/h. The other rectangular
x and y are in metre and t in second. The
component is:
acceleration of the particle at t = 5 s is:
a) 30 km/h
b) 30 2 km/h
a) 40 ms-2
b) 20 ms-2 c) 8 ms-2 d) zero
c) 30 3 km/h
d) 20 3 km/h
17. A bullet is fired horizontally with velocity of 80
7. A pendulum is suspended from the roof of a
m/s. During the first second:
train moving with acceleration a. The inclination
a) It falls 9.8 m
b) It falls 4.9 m
θ to the vertical is given by:
c)
It
does
not
fall
at
all
d)
It falls 8 m.
a) θ = 0
b) θ = tan-1(a/g)
18.
At
what
angle
θ
to
the
horizontal
should a ball
c) θ = tan-1(g/a)
d) θ = sin-1(a/g)
be projected so that the horizontal range is
8. A man moves on a cycle with a velocity of 4
equal to maximum height:
km/h. The rain appears to fall to him with a
a) θ = cot-1(1/4)
b) θ = cos-1(4)
velocity of 3 km/h vertically. The actual velocity
-1
c) θ = tan (1/4)
d) θ = sin-1(1/3)
of the rain is:
a) 7 km/h
b) (4/3) km/h
c) 5 km/h
d) 2.5 km/h
9. A projectile of mass m is fired with velocity v
from a point A at a n angle of 45o. Neglecting
air resistance, the magnitude of change in
momentum between the starting point A and
the arriving point B is:
a) 2 mv
b) ½ mv
c) mv 2
d) mv
PHYSICS ASSIGNMENT
Class XI Physics Assignment, October, 2012.
19. A particle is acted upon by a force of constant
magnitude which is always perpendicular to the
velocity of the particle. The motion takes place in a
plane. It follows that:
a) Its velocity is constant
b) its acceleration is constant
c) its KE is constant
d) its momentum is constant.
20. If the sum of two unit vectors is also a unit vector,
then the magnitude of their difference is:
a) 2
b) 3
c) 5
d)
8
21. One stone is projected horizontally from a 20
m high cliff with an initial speed of 10 m/s. A
second stone is simultaneously dropped from
that cliff. Then:
a) Both strike the ground with same velocity.
b) The ball with u = 10 m/s reaches the ground
first.
c) Both the balls hit the ground at the same
time.
d) One cannot say without knowing the height
of the cliff.
22. A body is projected at angle θ to the horizontal
with kinetic energy Ek. The potential energy at
the highest point of the trajectory is:
a) Ek
b) Ek cos2θ
2
c) Ek sin θ
d) Ek tan2θ
23. The velocity of projection of an oblique projectile is



v  3i  2 j m/s. The speed of the projectile at the
highest point of the trajectory is:
a) 3 m/s
b) 2 m/s
c) zero d) 1 m/s
24. When a body moves with constant speed along a
circle:
a) no work is done on it.
b) no acceleration is produced on the body.
c) no force acts on the body.
d) its velocity remains constant.
25. A mass of 2 kg is whirled in a horizontal circle by
means of a string at an initial speed of 5 rpm.
Keeping the radius constant, the tension in the string
is doubled. The new speed is nearly:
a) 14 rpm b) 10 rpm
c) 2.25 rpm
d) 7 rpm
26. For a particle in non uniform circular motion, the:
a) velocity is radial and acceleration is transverse
only.
b) velocity is transverse and acceleration is radial
only.
c) velocity is radial and acceleration has both radial
and transverse components.
d) velocity is transverse and acceleration has both
radial and transverse components.
27. A particle is fired with a velocity u, making an angle
θ with the horizontal. What is the change in
velocity when it is at the highest point?
a) u cosθ
b) u
c) u sinθ
d) u cos θ – u
Class XI Physics Assignment, October, 2012.


28. A particle has an initial velocity 3i  4 j and an


acceleration of 0.4i  0.3 j . Its speed after 10 s is:
a) 7 units
c) 8.5 units
b) 7 2 units
d) 5 2 units
29. A tachometer is a device used to measure:
a) gravitational pull
b) speed of rotation
c) surface tension
d) tension in a spring.
30. A particle is moving in a circle of radius R with
constant speed v. When the radius is doubled, its
centripetal force to keep the same speed must be:
a) doubled
b) halved
c) quadrupled
d) unchanged.
31. A wheel completes 2000 revolutions to cover a
distance of 9.5 km. The diameter of the wheel is:
a) 1.5 m
b) 1.5 cm
c) 7.5 m
d)7.5 cm
32. A stone tied to the end of a string 1 m long is
whirled in a horizontal circle with a constant speed. If
the stone makes 22 revolutions in 44 seconds, the
magnitude and direction of the acceleration of the
stone is:
a)  2 / 4 m/s2 along the radius towards the center.
b)  2 m/s2 along the radius away from the center.
c)  2 m/s2 along the radius towards the center.
d)  2 m/s2 along the tangent to the circle.
33. A stone is just released from the window of a train
moving along a straight horizontal track. The stone
will hit the ground following a :
a) straight path
b) circular path
c) parabolic path
d) hyperbolic path.
34. Which among the following is largest when the time
of flight of a projectile is greatest?
a) horizontal range
b) Maximum height
c) Angle of projectile with vertical
d) Both a) and b).
35. A cyclist is moving in a circular path with a uniform
speed of 200 cm/s. The change in velocity after half
revolution is:
a) zero
b) 200 cm/s
c) 4 m/s d) 40 cm/s
36. In the above question, change in velocity after
covering an angle of 90o is:
a) 2 m/s
b) 2 m/s c) 2 2 m/s d) 100 cm/s
37. A body is projected at an angle of 60o to the
horizontal with an initial kinetic energy E. Then
its KE at the maximum height is:
a) E/2
b) E/3
c) E/4
d) E/5
38. If H is the maximum height by a projectile and
T is the time of flight, then H/T2 is:
a) g/2
b) g/4
c) g/8
d) g/16
A ball is projected from the top of tower at an angle
60o to the horizontal. What happens to the
horizontal component of its velocity?
a) increases continuously
b) decreases continuously
c) first decreases and then increases.
d) remains unchanged.
MARYGIRI SENIOR SECONDARY SCHOOL
SREEKANDAPURAM
PHYSICS ASSIGNMENT
UNIT- LAWS OF MOTION
DOA: 06-10-2013
DOS: 11-10-2013
Class XI
1. For a body which is moving in a lift with uniform
velocity upwards:
a) weight decreases
b) weight increases
c) weight remains same
d) may increase or decrease depending on the
magnitude of velocity.
2. A body of mass 3 kg is suspended from a spring
balance arranged in a lift. When the lift is having a
downward acceleration of 5 m/s2, the reading shown by
the spring balance will be:
a) 4.5 kgwt. b) 1.5 kgwt. c) 3 kgwt. d) zero
3. A body of mass m is sliding on an inclined plane of
inclination θ. If µ is the coefficient of kinetic friction
involved , the frictional force acting is:
a) zero b) µmg d) µmg sinθ
d) µmg cosθ
4. A simple pendulum in a moving car is found to
be in equilibrium as shown in the figure. The
acceleration of the car is:
a) zero
b) g leftwards
c) 3g/4 rightwards
d) 4g/3 rightwards
5. A 2 kg mass is acted up on by two mutually
perpendicular forces 2 N and 4 N. Then the
acceleration produced on the body is:
a) 5 m/s2 b) 10 m/s2
c) 2 m/s2
d) 1 m/s2
6. While driving a car with a speed of 72 km/h, the
driver saw a child in the middle of the road. If he
took 5 seconds to stop the car just in front of the
child, what is the retarding force applied by the
break? (Given mass of the car = 500 kg, mass of
the driver = 50 kg )
a) 2.75 x 103 N b) 1.25 x 104 N
c) 2.75 x 104 N d) 1.25 x 103 N
7. A batsman hits a cricket ball of mass 200g
delivered with a velocity of 15 m/s. If the time of hit
is 0.1 s and after hit it moves with a velocity of 25
m/s exactly in the opposite direction, the average
force exerted on the ball by hit is:
a) 8 N
b) 800 N
c) 80N
d) 100 N
Class XI Physics Assignment, October, 2012.
8. Out of the following, the self adjusting force is:
a) sliding friction
b) static friction
c) dynamic friction
d) limiting friction
9. What is the tension acting on the string in the
figure shown below.
a) 106.6 N
b) 83 N
c) 12 N
d) 206 N
10. A cyclist while taking a curved path leans to
the vertical by an angle 1o. If he doubles his speed
the angle of leaning should be adjusted to:
a) 1o
b) 2o
c) 4o
d) 0.5o
11. The momentum of a body at any time t is given
by the equation P = Po sin ωt. The maximum value
of the magnitude of the force acting on it is:
a) 0
b) P
c) Poω
d) Po / ω
12. A body of mass m is resting on an inclined
plane which makes an angle θ with the horizontal.
As θ increases, the normal reaction of the plane:
a) remains un altered. b) increases
c) decreases d) increases and then decreases.
13. Two moving particles have their masses in the
ratio 2:3. They collide together and then comes to
rest. Their speeds before collision were in the
ratio:
a) 1 : 1
b) 2 : 3
c) 3 : 2
d) 0 : 3
14. A body of mass m is kept pressed against a
vertical wall by a force F = Mg. If 0.5 is the
coefficient of kinetic friction between the wall and
the body, the acceleration with which it falls down
is:
a) 0.5 g
b) g
c) 1.5 g
d) zero
15. A body of mass 2 kg slides down a rough
inclined plane with uniform velocity. The inclination
of the plane is 30o. The coefficient of friction is:
a) zero
b)
1
3
c)
3
2
d)
1
2
16. A body is there on a rough inclined plane of
inclination θ where it is pushed down with an
acceleration g sinθ by a force F. If µ is the
coefficient of kinetic friction, the force F is:
a) zero
b) mg
c) mg sinθ
d) µmg cosθ
permitted?
a) 5 m/s b) 10 m/s
c) 10 2 m/s
d) 5 2 m/s
26. On a smooth plane surface, two blocks A and
B are accelerated by applying a force of 15 N on
A. If mass of B is twice that of A, the force on B is:
a) 30 N
b) 15 N
c) 10 N
d) 5 N
17. A ball of momentum 50 Ns is stopped by a
force of 500 N. The time taken is:
a) 1 s
b) 10 s
c) 0.1 s
d) 0.05 s
18. A string is suspended vertically from the hook
of a spring balance. A monkey move along the
string. The spring balance will show its correct
weight when:
a) the monkey is at rest.
b) the monkey is moving up or down with uniform
velocity.
27. Force is applied on an object of mass 2 kg at
rest on a frictionless horizontal surface as
indicated on the graph. After one second, the
speed of the object in m/s is:
a) 7.5
b) 12.5
c) 15
d) 25
c) the monkey is having upward or downward
acceleration.
d) both a) and b).
19. A body moves a distance 100 m along a
straight line . The force acting on it is 10 N and the
work done in the process is 500 J. The angle
between directions of force and displacement is:
a) 0
b)30o
c) 60o
d) 90o
20. The position co-ordinate of a body of mass
0.003 kg at the time t is x = 3 t – 4 t2 + t3. The initial
force acting it is:
a) zero b) 0.024 N c) -0.024 N d) 0.009 N
21. A box is there on the top of a truck moving
horizontally. The coefficient of limiting of friction
between the two being µ. The maximum
acceleration the truck can have without the box
sliding is:
a) g
b) g/µ
c) µg
d) µ2g
22. A body of mass 4 kg is there on a rough
horizontal surface of coefficient of friction 0.3. A
horizontal force of 6 N is applied on the body. The
ratio of frictional force developed to the normal
reaction is ( Take g = 10 m/s2.):
a) 3/10
b) 3/20
c) 1
d) zero
23. A machine gun fires 120 bullets per minute.
The mass of each bullet is m and its velocity is v.
The force exerted on the gun is:
a) mv
b) 2 mv
c) 120 mv
d) mv/2
24. What is the maximum speed of a car taking a
turn of radius 30 m on a level road if the coefficient
of friction between the tyres and the road is 0.4?
a) 5.42 m/s b) 10.84 m/s c) 21.68 m/s d) 8.32 m/s
25. When the road is dry and the coefficient of
friction is µ, the maximum speed of a car in a
circular path is 10 m/s. If the road becomes wet
and µI = µ/2, what is the maximum speed
Class XI Physics Assignment, October, 2012.
26. A boy stands on a weighing machine inside a
lift. When the lift is going down with acceleration
g/4, the machine shows a reading of 30 kgf. When
the lift goes upwards at acceleration g/4, the
reading would be:
a) 18 kgf b) 37.5 kgf c) 50 kgf d) 67.5 kgf
27. A ball of mass m is thrown vertically upwards.
What is the rate at which the momentum of the ball
changes?
a) zero
b) mg
c) 2 mg
d) mg/2
28. The engine of a car produces an acceleration
of 6 m/s2 on the car. If this car pulls on another car
of same mass, then the acceleration would be:
a) 6 m/s2 b) 12 m/s2
c) 3 m/s2 d) 1.5 m/s2.
29. In a game of tug of war, a condition of
equilibrium exists. Both the teams