a body starts from rest with uniform acceleration. if its velocity … · 2020. 8. 20. · a body...

A body starts from rest with uniform acceleration.

If its velocity after n second is u, then its

displacement in the last two seconds is

MENTI QUIZ - 40

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01

The speed of a body moving with uniform

acceleration is u. This speed is doubled while

covering a distance S. When it covers an

additional distance S, its speed would become


02

A bird flies for 4 s with a velocity of |t–2| m/s a

straight line, where t is time in seconds. It covers a

distance of

(A) 2m (B) 4m

(C) 6m (D) 8m


03

A particle is projected with velocity v0 along x-axis.

The deceleration on the particle is proportional to the

square of the distance from the origin i.e., a = –ax2.

The distance at which the particle stop is

(A) (B)

(C) (D)


04

03

2a

u1

203

2a

u

2

03

2a

u

12 303

2a

u

A small body of mass m slides down from the top of a

hemisphere of radius r. The surface of block and

hemisphere are frictionless. The height at which the

body lose contact with the surface of the sphere is


05

A particle is projected with a velocity v such that its

range on the horizontal plane is twice the greatest height

attained by it. The range of the projectile is (where g is

acceleration due to gravity)


06

A man standing on the roof a house of height h throws

one particle vertically downwards and another particle

horizontally with the same velocity u. The ratio of their

velocities when they reach the earth’s surface will be


07

A stone is projected from the ground with velocity

50 m/s at an angle of 30°. It crosses a wall after 3

sec. How far beyond the wall the stone will strike

the ground (g = 10m/sec2)

(A) 90.2m (B) 89.6m

(C) 86.6m (D) 70.2m


08

A connon on a level plane is aimed at an angle q above

the horizontal and a shell is fired with a muzzle velocity

v0 towards a vertical cliff a distance D away. Then the

height from the bottom at which the shell strikes the side

walls of the cliff is

(A) (B)

(C) (D)


09

2

2 2

0

2sin

2 sin

DD

u

2

2 2

0

2cos

2 cos

DD

u

2

2 2

0

2tan

2 cos

DD

u

2

2 2

0

2tan

2 sin

DD

u

A particle of mass m, initially at rest, is acted upon by a

variable force F for a brief interval of time T. It begins to

move with a velocity u after the force stops acting. F is

shown in the graph as a function of time. The curve is a

semicircle


10

A force acts on a 2 kg object so that its position is

given as a function of time as x = 3t2+5. What is

the work done by the force in first 5 seconds

(A) 850J (B) 900J

(C) 950J (D) 875J


11

Three blocks, A, B and C are lying on a smooth horizontal

surface, as shown in the figure. A and B have equal masses, m

while C has mass M. block A is given an brutal speed v towards

B the due to which it collides with B perfectly inelastically. The

combined mass collides with C, also perfectly inelastically 5/6th

of the initial kinetic energy is lost in whole process. What is

value of M/m

(A) 4 (B) 5

(C) 3 (D) 2


12

A block of mass m is kept on a platform which starts

from rest with constant acceleration g/2 upward, as

shown in fig. Work done by normal reaction on

block in time t is


13

A body of mass 1 kg falls freely from a height of 100 m

on a platform of mass 3 kg which is mounted on a

spring having spring constant k = 1.25×106N/m. The

body sticks to the platform and the spring’s maximum

compression is found to be x. Given that g = 10ms–2,

the value of x will be close to

(A) 2cm (B) 8cm

(C) 80cm (D) 40cm


14

A body of mass m1 moving with an unknown velocity of

undergoes a collinear collision with a body of mass

m2 moving with a velocity After collision, m1 and m2

move with velocities of and respectively. If m2 =

0.5m1 and v3 =0.5v1, then v1 is


15

1ˆ,iu

2ˆ.iu

3iu4ˆ,iu

A particle of mass ‘m’ is moving with speed ‘2v’ and collides

with a mass ‘2m’moving with speed ‘v’ in the same direction.

After collision, the first mass is stopped completely whi8le the

second one splits into two particles each of mass ‘m’, which

move at angle 45° with respect to the original direction The

speed of each of the moving particle will be

(A) (B)

(C) (D)


16

/ 2 2u 2 2u

2u / 2u

A wedge of mass M = 4m lies on a frictionless plane. A

particle of mass m approaches the wedge with speed v.

There is no friction between the particle and the plane or

between the particle and the wedge. The maximum height

climbed by the particle on the wedge is given by


17

Two particles, of masses M and 2M, moving, as shown, with

speed of 10m/s and 5m/s, collide elastically at the origin.

After the collision, they move along the indicated directions

with speeds v1 and v2, respectively. The values of v1 and v2

are nearly

(A) 3.2m/s and 6.3m/s

(B) 3.2m/s and 12.6m/s

(C) 6.5m/s and 6.3m/s

(D) 6.5m/s and 3.2m/s


18

A body of mass 2 kg makes an elastic collision with

a second body at rest and continues to move in the

original direction but with one fourth of its

original speed. What is the mass of the second

body

(A) 1.8kg (B) 1.2kg

(C) 1.5kg (D) 1.0kg


19

Body A of mass 4m moving with speed u collides

with another body B of mass 2m, at rest. The

collision is head on and elastic in nature. After the

collision the fraction of energy lost by the colliding

body A is

(A) 1/9 (B) 8/9

(C) 4/9 (D) 5/9


20

A force F = 30+10y acts on a particle in y-direction

where F is in Newton and y in meter. Work done

by this force to move the particle from y = 0 to y =

1m is

(A) 30J (B) 5J

(C) 25J (D) 20J


21

The elastic limit of brass is 379Mpa. What should

be the minimum diameter of a brass rod if it is to

support a 400 N load without exceeding its elastic

limit

(A) 1.16mm (B) 1.7mm

(C) 1.36mm (D) 1.00mm


22

In an experiment, brass and steel wires of length 1m each

with area of cross section imm2 are used. The wires are

connected in series and one end of the combined wire is

connected to a rigid support and other end is subjected to

elongation. The stress required to produce a net elongation

of 0.2mm is (Given, the young’s Modulus for steel and

brass are respectively, 120×109N/m2 and 60×109N/m2)

(A) 0.2×106N/m2 (B) 8.0×106N/m2

(C) 1.8×106N/m2 (D) 1.2×106N/m2


23

When a block of mass M is suspended by a long

wire of potential energy stored in the extended

wire is


24

A uniform cylinder of length L and mass M having cross

sectional area A is suspended, with its length vertical, from a

fixed point by a massless spring such that it is half submerged

in a liquid of density at equilibrium position. The extension

x0 of the spring when it is in equilibrium is


25

If ‘M’ is the mass of water that rises in a capillary

tube of radius ‘r’, then mass of water which will

rise in a capillary tube of radius ‘2r’ is

(A) 4M (B) M

(C) 2M (D) M/2


26

The ratio of surface tensions of mercury and water is given

to be 7.5 while the ratio of their densities is 13.6. Their

contact angles, with glass, are close to 135° and 0°,

respectively. It is observed that mercury gets depressed by

an amount h in a capillary tube of radius r1. while water

raises by the same amount h in a capillary tube of radius

r2. The ratio (r1/r2), is then close to

(A) 2/3 (B) 3/5

(C) 2/5 (D) 4/5


27

A soap bubble, having radius of 1mm, is blown from a

detergent solution having a surface tension of 2.5×10–

2N/m. The pressure inside the bubble equals at a point

Z0 below the free surface of water in a container. Taking

g = 10m/s2 density of water = 103kg/m3, the value of Z0 is

(A) 100cm (B) 10cm

(C) 1cm (D) 0.5cm


28

A small sphere of radius ‘r’ falls from rest in a viscous

liquid. As a result, heat is produced due to viscous

force. The rate of production of heat when the sphere

attains its terminal velocity, is proportional to:

(A) r3 (B) r2

(C) r5 (D) r4


29

Water from a pipe is coming at a rate of 100 liters

per minute. If the radius of the pipe is 5 cm, the

Reynolds number for the flow is of the order of

(density of water =1000kg/m3, coefficient of

viscosity of water = 1mPas)

(A) 106 (B) 103

(C) 104 (D) 102


30

A submarine experiences a pressure of 5.05×106Pa at a

depth of d1 in a sea. When it goes further to a depth of

d2, it experiences a pressure of 8.08×106Pa. Then d2–

d1 is approximately (density of water = 103kg/m3 and

acceleration due to gravity = 10ms–2)

(A) 500m (B) 400m

(C) 300m (D) 600m


31

A solid, sphere, of radius R acquires a terminal

velocity v1 when falling (due to gravity) through a

viscous fluid having a coefficient of viscosity The

sphere is broken into 27 identical solid spheres. If each

of these spheres acquires a terminal velocity, v2, when

falling through the same fluid, the ratio (v1/v2) equals

(A) 1/27 (B) 1/9

(C) 27 (D) 9


32

Two holes of unequal diameters d1 and d2 (d1>d2) are

cut in a metal sheet. If the sheet is heated

(A) Both d1 and d2 will decrease

(B) Both d1 and d2 will increase

(C) d1 will increase, d2 will decrease

(D) d1 will decrease, d2 will increase


33

A hollow sphere of mass ‘M’ and ‘R’ is rotating with

angular frequency ‘w’. It suddenly stops rotating and 75%

of kinetic energy is converted to heat. If ‘S’ is the specific

heat of the material in J/kg K then rise in temperature of

the sphere is (M.I. of hollow sphere = )


34

22

3MR

A faulty thermometer has its lower fixed point

marked as –10°C and upper fixed point marked as

110°. If the temperature of the body shown in this

scale is 62°, the temperature shown on the Celsius

scale is

(A) 72°C (B) 82°C

(C) 60°C (D) 42°C


35

The figure shows a glass tube (linear co-efficient of

expansion is a) completely filled with a liquid of volume

expansion co-efficient g. On heating length of the liquid

column does not change. Choose the correct relation

between g and a

(A) g = a

(B) g = 2a

(C) g = 3a

(D) g = a/3www.gangwarinstitue.com Contact : 8400-582-582, 8604-582-582

36

When the temperature of a gas is raised from

27°C to 90°C, the percentage increase in the r.m.s.

velocity of the molecules will be

(A) 10% (B) 15%

(C) 20% (D) 17.5%


37

The pressure and temperature of an ideal gas in a

closed vessel are 720 kPa and 40°C respectively. If

1/4th of the gas is released from the vessel and the

temperature of the remaining gas is raised to

353°C, the final pressure of the gas is

(A) 1440kPA (B) 1080kPA

(C) 720kPA (D) 540kPA


38

One mole of an ideal monatomic gas requires 210J

heat to raise the temperature by 10K, when heated

at constant temperature. If the same gas is heated

at constant volume to raise the temperature by

10K then heat required is

(A) 238J (B) 126J

(C) 210J (D) 350J


39

P-V plots for two gases during adiabatic process

are shown in the figure. Plots 1 and 2 should

correspond respectively to

(A) He and O2

(B) O2 and He

(C) He and Ar

(D) O2 and N2


40

In an adiabatic change, the pressure P and

temperature T of a monoatomic gas are related by

the relation where c equals

(A) 5/3 (B) 2/5

(C) 3/5 (D) 5/2


41

,CP T

Heat is supplied to a diatomic gas at constant

pressure. The ratio of DQ:DU:DW

(A) 5 : 3 : 2 (B) 5 : 2 : 3

(C) 7 : 5 : 2 (D) 7 : 2 : 5


42

N moles of an ideal diatomic gas in a cylinder at

temperature T. Suppose on supplying heat to the gas,

its temperature remains constant but n moles get

dissociated into atoms. Heat supplied to the gas is


43

A solid maintained at t10°C is kept in an evacuated

chamber at temperature t20°C (t2>>t1). The rate of

heat absorbed by the body is proportional to

(A) (B)

(C) (D)


44

4 4

2 1t t 4 4

2 1( 273) ( 273)t t

2 1t t 2 2

2 1t t

A partition wall has two layers A and B in contact,

each made of a different material. They have the same

thickness but the thermal conductivity of layer A is

twice that of layer B. If the steady state temperature

difference across the wall is 60K, then the

corresponding difference across the layer A is

(A) 10K (B) 20K

(C) 30K (D) 40K


45

a body starts from rest with uniform acceleration. if its velocity … · 2020. 8. 20. · a body...

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