CBSE Questions for Class 11 Engineering Physics Motion In A Straight Line Quiz 11 - MCQExams.com

A particle moves half the time of its journey with velocity u. The rest of the half time it moves with two velocities $$v_1$$ and $$v_2$$ such that half the distance it covers with $$v_1$$ and the other half with $$v_2$$. Find the net average velocity assume straight line motion:
  • $$\dfrac { u\left( v_{ 1 }+v_{ 2 } \right) +2v_{ 1 }v_{ 2 } }{ 2\left( v_{ 1 }+v_{ 2 } \right) } $$
  • $$\dfrac { 2u\left( v_{ 1 }+v_{ 2 } \right) }{ 2u+v_{ 1 }+v_{ 2 } } $$
  • $$\dfrac { u\left( v_{ 1 }+v_{ 2 } \right) }{ 2v_{ 1 } } $$
  • $$\dfrac { 2v_{ 1 }v_{ 2 } }{ u+v_{ 1 }+v_{ 2 } } $$
The velocity of a particle varies with time as shown below. The distance travelled by the particle during $$t=2s$$ and $$t=6s$$ is:
1742669_f99ec490552d4f31bb1897fbc0b7ccf8.png
  • $$ 2\pi m $$
  • $$ (2\pi +40 m) $$
  • $$ 4\pi m $$
  • $$40 m$$
The maximum velocity attained by the car is
  • $$\dfrac { \alpha \beta }{ 2\left( \alpha +\beta \right) } t$$
  • $$\dfrac { \alpha \beta }{ \alpha +\beta } t$$
  • $$\dfrac { 2\alpha \beta }{ \alpha +\beta } t$$
  • $$\dfrac { 4\alpha \beta }{ \alpha +\beta } t$$
The time after which they are closet to each other
  • 1/3 s
  • 8/3 s
  • 1/5 s
  • 8/5 s
The velocity of the body at any instant is
  • $$\dfrac { M+{ 2 }Nt^{ 4 } }{ 4 } $$
  • $$2N$$
  • $$\dfrac { M+{ 2 }N }{ 4 } $$
  • $$2Nt^3$$
A particle is found to be at rest when seen from a $$ S_1 $$ and moving with a constant velocity when seen from another frame $$ S_2 $$ select the possible options: 
  • Both the frames are non-inertial
  • $$ S_1 $$ is inertial and $$ S_2 $$ is non-inertial
  • Both the frames are inertial
  • $$ S_1 $$ is non-inertial and $$ S_2 $$ is inertial
The distance covered by the second body when they meet is
  • 8 m
  • 16 m
  • 24 m
  • 32 m
The velocity of the body at the end of 1 s from the start is
  • $$2N$$
  • $$\dfrac{M+2N}{4}$$
  • $$2(M+N)$$
  • $$\dfrac{2M+N}{4}$$
The speed-time graph of a body is straight line parallel to time axis. The body has:
  • uniform acceleration
  • uniform speed
  • variable speed
  • variable acceleration
A stone is dropped from the top of the tower . Its speed after it has fallen $$ 20\,m $$ is   
 (Take $$ g = 10\, ms^{-2} $$ ) 
  • $$ -10\, ms^{-1} $$
  • $$ 10\, ms^{-1} $$
  • $$ -20\, ms^{-1} $$
  • $$ 20\, ms^{-1} $$
Starting from rest at the top of an inclined plane a body reaches the bottom of the inclined plane in 4 second. In what time dies the body cover one-fourth the distance starting from rest at the top?
  • 1 second
  • 2 second
  • 3 second
  • 4 second
An iron sphere of mass $$10\ kg$$ has the same diameter as an aluminium sphere of mass is $$3.5\ kg$$. Both spheres are dropped simultaneously from a tower. When they are $$10\ m$$ above the ground, the have the same
  • acceleration
  • momenta
  • potential energy
  • kinetic energy
A book lying on a table is an example of 
  • a body at rest
  • a body in motion
  • a body neither at rest nor motion
  • none of these
A body falls from rest in the gravitational field of the earth. The distance travelled in the fifth second of its motion is $$ (g = 10\, m/s^2) $$ 
  • $$ 25 \,m $$
  • $$ 45\,m $$
  • $$ 90\,m $$
  • $$ 125\,m $$
Rewrite the sentence using proper alternative.
The total energy of an falling freely toward the ground ____
  • decreases
  • remains unchanged
  • increases
  • increases in the beginning and then decreases
On another planet, a marble is released from rest at the top of a high cliff. It falls $$4.00 m$$ in the first $$1 s$$ of its motion. Through what additional distance does it fall in the next $$1 s$$?
  • $$4.00m$$
  • $$8.00m$$
  • $$12.0m$$
  • $$16.0m$$
  • $$20.0m$$
An electron with a speed of $$3.00 \times 10^6 m/s$$ moves into
a uniform electric field of magnitude $$1.00 \times10^3 \,N/C$$. The field lines are parallel to the electrons velocity and pointing in the same direction as the velocity. How far does the electron travel before it is brought to rest?
  • $$2.56 \,cm$$
  • $$5.12 \,cm$$
  • $$11.2 \,cm$$
  • $$3.34 \,m$$
  • $$4.24 \,m$$

Relative to another coordinate system $$\mathrm{S}'$$ (denoted by single prime) moving with a vertical velocity $$\vec{\mathrm{v}}_{0}$$, the equation of motion of the object becomes
  • $$\displaystyle \mathrm{m}(\frac{\mathrm{d}\vec{\mathrm{v}}}{\mathrm{d}\mathrm{t}})=-\mathrm{m}\vec{\mathrm{g}}-\mathrm{b}\vec{\mathrm{v}}$$
  • $$m\left ( \frac{d\vec{\mathrm{v}}}{dt} \right )=-m\vec{g}-b(\vec{\mathrm{v}}-\vec{\mathrm{v_{0}}})$$
  • $$m\left [ \left ( \frac{d\vec{\mathrm{v}}}{dt}-\vec{\mathrm{v_{0}}} \right ) \right ]=-m\vec{g}-b(\vec{\mathrm{v}}+\vec{\mathrm{v_{0}}})$$
  • $$m\left ( \frac{d\vec{\mathrm{v}}}{dt} \right )=m(\vec{g}-\vec{\mathrm{v_{0}}})-b\vec{\mathrm{v}}$$
A particle moves with a non zero initial velocity $${ v }_{ 0 }$$ and retardation $$kv$$, where $$v$$ is the velocity at any time $$t$$.
  • The particle will cover a total distance $$\cfrac {{ v }_{ 0 }}{k}$$
  • The particle comes to rest at $$t=\cfrac{1}{k}$$
  • Particle continues to move for long time
  • at time $$\cfrac{1}{\alpha}, v=\cfrac {{ v }_{ 0 }}{2}$$
A body of mass m is dropped from a height of h. Simultaneously another body of mass 2m is thrown up vertically with such a velocity v that they collide at height $$\dfrac {h}{2}$$. If the collision is perfectly inelastic, the velocity of combined mass at the time of collision with the ground will be-
  • $$\sqrt {\dfrac {5gh}{4}}$$
  • $$\sqrt {gh}$$
  • $$\sqrt {\dfrac {gh}{4}}$$
  • None of these
A particle is projected with a velocity $$u$$ in horizontal direction as shown in the figure. Find $$u$$(approx.) so that the particle collides orthogonally with the inclined  plane of the fixed wedge.

75201.jpg
  • $$10  \ m/s$$
  • $$20  \ m/s$$
  • $$10\sqrt{2}\ m/s$$
  • None of these
The displacement of a particle moving in a straight line is given by $$x=16t-2t^{2}$$ (where, $$x$$ is in meters and $$t$$ is in second). The distance traveled by the particle in $$8$$ seconds [starting from $$t$$ $$=$$ 0] is
  • $$24 m$$
  • $$40 m$$
  • $$64 m$$
  • $$80 m$$
A water tap leaks such that water drops fall at regular intervals. Tap is fixed $$5\ m$$ above the ground. First drop reaches the ground and at that very instant third drop leaves the tap. At this instant the second drop is at a height of

134244.jpg
  • $$3\ m$$
  • $$4.5\ m$$
  • $$3.75\ m$$
  • $$2.5\ m$$
A ball is thrown vertically upwards (relative to the train) in a compartment of a moving train. The face of the person sitting inside the compartment is towards engine of the train.
  • The ball will maintain the same horizontal velocity as that of the person (or the compartment) at the time of throwing.
  • If the train is accelerating then the horizontal velocity of the ball will be different from that of the train velocity, at the time of throwing.
  • If the ball appears to be moving backward to the person sitting in the compartment it means that speed of the train is increasing.
  • If the ball appears to be moving ahead of the person sitting in the compartment it means the train's motion is retarding.
Using the table given below where the values of velocity at the end of t seconds for a body under linear motion are given
$$V (m\:s^{-1})$$
0

6
12
24
30
36
42
$$t (s)$$
0

2
4
8
10
12
14
What can be concluded about the motion of the body?
  • It moves with uniform speed.
  • It moves with uniform motion
  • It moves with uniform velocity
  • It moves with uniform acceleration
A circus girl throws three rings upwards one after the other at equal intervals of half a second. She catches the first ring half second after the third was thrown. Then,
($$\mathrm{g}=$$ acceleration due to gravity)
  • the velocity of projection of rings is $$\displaystyle \frac{3\mathrm{g}}{4}$$
  • the maximum height attained by rings is $$\displaystyle \frac{\mathrm{g}}{32}$$
  • when the first ring returns to her hand, the second ring was coming downwards and it is on the height of $$\displaystyle \frac{\mathrm{g}}{4}$$ (from the ground).
  • when the first ring returns to her hand, the third ring was going up and has travelled a distance of $$\displaystyle \frac{\mathrm{g}}{4}$$ (from the ground).
Two identical balls are shot upward one after another at an interval of $$2\ s$$ along the same vertical line with same initial velocity of  $$40\ ms^{-1}$$ The height at which the balls collide is
  • $$50\ m$$
  • $$75\ m$$
  • $$100\ m$$
  • $$125\ m$$
A particle is thrown upwards from ground. It experiences a constant resistance force which can produce a retardation of $$\displaystyle 2\  ms^{-2}.$$ The ratio of time of ascent to time of descent is (g= $$\displaystyle 10  \ m/s^{2}$$)
  • 1 : 1
  • $$\displaystyle \sqrt{\frac{2}{3}}$$
  • $$\displaystyle \frac{2}{3}$$
  • $$\displaystyle \sqrt{\frac{3}{2}}$$
A person sitting in the rear end of the compartment throws a ball towards the front end.The ball follows a parabolic path.The train is moving with velocity of $$20\ m/s$$.A person standing outside on the ground also observes the ball.How will the maximum heights $$y_m$$ attained and the ranges $$R$$ seen by the thrower and the outside observer compare with each other?
  • same $$y_m$$ different $$R$$
  • same $$y_m$$ and $$R$$
  • differently $$y_m$$ same $$R$$
  • differently $$y_m$$ and $$R$$
Mass $$A$$ is released from rest at the top of a frictionless inclined plane $$18 m$$ long and reaches the bottom $$3 s$$ later. At the instant when $$A$$ is released, a second mass $$B$$ is projected upwards along the plate from the bottom with a certain initial velocity. Mass $$B$$ travels a distance up the plane, stops and returns to the bottom so that it arrives simultaneously with $$A$$. The two masses do not collide. Initial velocity of $$B$$ is


135164.png
  • $$4\:ms^{-1}$$
  • $$5\:ms^{-1}$$
  • $$6\:ms^{-1}$$
  • $$7\:ms^{-1}$$
A ball is thrown vertically upwards from the ground and a student gazing out of the window sees it moving upward past him at $$\displaystyle 10 \ ms^{-1}.$$ The window is at  $$15$$ m above the ground level. The velocity of ball $$3\ s$$ after it was projected from the ground is (take $$ \ g= 10 \ ms^{-2} $$)
  • $$10 \ ms^{-1},$$ up
  • $$\displaystyle 20\ ms^{-1},$$ up
  • $$\displaystyle 20\ ms^{-1},$$ down
  • $$\displaystyle 10\ ms^{-1},$$ down
A lift start from rest. Its acceleration is plotted against time. When it comes to rest its height above its starting point is

242571_362afe8a05ad4b6a817b1cb74de54d8a.png
  • $$20\ m$$
  • $$64\ m$$
  • $$32\ m$$
  • $$36\ m$$
A particle is projected vertically upwards and reaches the maximum height $$H$$ at a time $$t=T$$. The height of the particle at any time $$t (< T)$$ will be
  • $$\displaystyle g\left ( t-T \right )^{2}$$
  • $$\displaystyle H-g\left ( t-T \right )^{2}$$
  • $$\displaystyle \frac{1}{2}g\left ( t-T \right )^{2}$$
  • $$\displaystyle H-\frac{1}{2}g\left ( T-t \right )^{2}$$
A ball is dropped from a height of 49 m. The wind is blowing horizontally. Due to wind a constant horizontal acceleration is provided to the ball. Choose the correct statement (s). [Take g= 9.8 $$\displaystyle ms^{-2}$$]
  • Path of the ball is a straight line
  • Path of the ball is a curved one
  • The time taken by the ball to reach the ground is 3.16 s
  • Actual distance travelled by the ball is more than 49 m
The velocity of a particle at time $$t=0$$ is $$2m/s$$. A constant acceleration of $$2m/s^{2}$$ acts on the particle for $$2$$ seconds at an angle of $$60$$$$^{\circ}$$ with its initial velocity. The magnitude of velocity and displacement of particle at the end of $$t=2s$$ respectively are:
  • $$2$$$$\sqrt{7}$$ m/s, $$4$$$$\sqrt{3}$$ m
  • $$2$$$$\sqrt{3}$$ m/s, $$4$$$$\sqrt{7}$$ m
  • $$4$$$$\sqrt{7}$$ m/s, $$2$$$$\sqrt{3}$$ m
  • $$4$$$$\sqrt{3}$$ m/s, $$2$$$$\sqrt{7}$$ m
A car moving along a straight highway with a speed of $$126 kmph$$ is brought to a stop within a distance of $$200 m$$. What is the acceleration of the car and how long does it take for the car to stop?
  • $$-3.06 ms^{-2}, 11.43 s$$
  • $$-6.03 ms^{-2}, 11.43 s$$
  • $$-3.06 ms^{-2}, 10.34 s$$
  • $$-6.03 ms^{-2}, 10.34 s$$
A car is travelling on a straight road. The maximum velocity the car can attains is $$\displaystyle 24 ms^{-1}.$$ The maximum acceleration and deceleration it can attain are $$\displaystyle 1 ms^{-2}$$ and $$\displaystyle 4ms^{-2}$$ respectively. The shortest time the car takes from rest to rest in a distance of 500 m is,
  • 22.4 s
  • 30 s
  • 11.2 s
  • 35.8 s
Starting from rest a particle is first accelerated for time $$\displaystyle t_{1}$$ with constant acceleration $$\displaystyle a_{1}$$ and then stops in time $$\displaystyle t_{2}$$ with constant retardation $$\displaystyle a_{2}.$$ Let $$\displaystyle v_{1}$$ be the average velocity in this case and $$\displaystyle s_{1}$$ the total displacement. In the second case

it is accelerated for the same time $$t_1$$ with constant acceleration $$2a_1$$ and come to rest with constant retardation $$\displaystyle a_{2}$$ in time $$\displaystyle t_{3}.$$ If $$\displaystyle v_{2}$$ is the average velocity in this case and $$\displaystyle s_{2}$$ the total displacement, then
  • $$\displaystyle v_{2}=2v_{1}$$
  • $$\displaystyle 2v_{1}< v_{2}< 4v_{1}$$
  • $$\displaystyle S_{2}2=S_{1}$$
  • $$\displaystyle 2S_{1} < S_{2}< 4S_{1}$$
Two balls were thrown vertically upwards with different velocities, what is the shape of the graph between distance between the balls and time before either of the two collide with ground?
  • Straight line passing through origin
  • Parabola
  • Circle
  • None of the above
Net force acting on a particle of mass 2 kg is 10 N in north direction. At t = 0, particle was moving eastwards with 10 m/s. Find displacement and velocity of particle after  2 s.
  • $$\displaystyle 10\sqrt{5}$$ m at $$\displaystyle \cot^{-1}(2)$$ from east towards north, $$\displaystyle 10\sqrt{2}ms^{-1}\:at\:45^{\circ}$$ from east towards north.
  • $$\displaystyle 10\sqrt{2}$$ m at $$\displaystyle \cot^{-1}(2)$$ from east towards north, $$\displaystyle 10\sqrt{2}ms^{-1}\:at\:45^{\circ}$$ from east towards north.
  • $$\displaystyle 10\sqrt{5}$$ m at $$\displaystyle \cot^{-1}(2)$$ from east towards north, $$\displaystyle 10\sqrt{5}ms^{-1}\:at\:45^{\circ}$$ from east towards north.
  • $$\displaystyle 10\sqrt{2}$$ m at $$\displaystyle \cot^{-1}(2)$$ from east towards north, $$\displaystyle 10\sqrt{5}ms^{-1}\:at\:45^{\circ}$$ from east towards north.
Trajectory of two particles projected from origin with speed $$\displaystyle v_{1}$$ and $$\displaystyle v_{2}$$ and angles $$\displaystyle \theta _{1}$$ and $$\displaystyle \theta _{2}$$ with positive x- axis respectively as shown in the figure given that $$\displaystyle g=-10m/s^{2}(j)$$. Choose the correct option related to diagram :
332652_04cc63e4042f46d3b21e338e85f766ce.png
  • $$\displaystyle v_{1}-v_{2}=2v_{1}$$
  • $$\displaystyle \theta_{2}-\theta _{1}=2\theta _{1}$$
  • $$\displaystyle 3(v_{1}-v_{2})=0$$
  • $$\displaystyle 3(\theta_{1}-\theta_{2})=-\theta _{1}$$
A particle travels so that its acceleration is given by $$\vec{a}=5\,cos\,t\hat {i}-3\,sin\,t\hat {j}$$. If the particle is located at $$(-3,2)$$ at time $$t=0$$ and is moving with a velocity given by $$(-3\hat {i}+2\hat {j})$$. Find
(i) the velocity $$\begin{bmatrix}\vec{v}=\int \vec{a}.dt\end{bmatrix}\:time\:t$$
(ii) the position vector $$[\vec{r}=\int \vec{v}.dt]$$ of the particle at time $$(t>0)$$.
  • (i)$$\;\vec{v}=(5sin\;t-3)\hat {i}+(3cos\;t-1)\hat {j}$$, (ii)$$\;\vec{s}=(2-5cos\;t-3t)\hat {i}+(2+3sin\;t-t)\hat {j}$$
  • (i)$$\;\vec{v}=(3sin\;t-3)\hat {i}+(3cos\;t-1)\hat {j}$$, (ii)$$\;\vec{s}=(2-5cos\;t-3t)\hat {i}+(2+3sin\;t-t)\hat {j}$$
  • (i)$$\;\vec{v}=(4sin\;t-3)\hat {i}+(3cos\;t-1)\hat {j}$$, (ii)$$\;\vec{s}=(2-5cos\;t-3t)\hat {i}+(2+3sin\;t-t)\hat {j}$$
  • None of these
A thief is running away on a straight road with a speed of $$9  \ ms^{-1}$$. A police man chases him on a jeep moving at a speed of $$10 \  ms^{-1}$$ If the instantaneous separation of the jeep from the motorcycle is 100 m, how long will it take. for the police man to catch the thief?
  • 1s
  • 19s
  • 90s
  • 100 s
A stone is thrown upwards from a tower with a velocity $$50\, ms^{-1}$$. Another stone is simultaneously thrown downwards from the same location with a velocity $$50\,ms^{-1}$$ . When the first stone is at the highest point, the relative velocity of the second stone with respect to the first stone is (assume that second stone has not yet, reached the ground  
  • Zero
  • $$50\, ms^{-1}$$
  • $$100\, ms^{-1}$$
  • $$150\, ms^{-1}$$
A ballon starts rising from the ground with an acceleration of $$1.25 \ m/s^{2}$$. After $$8\ s$$ a stone is released from the balloon. The stone will (take $$g=10\ m/s^{2}$$)
  • have a displacement of 50 m
  • cover a distance of 40 m in reaching the ground
  • reach the ground in 4 s
  • reach the ground in 16 s
Which of the following is not an example of acceleration?
  • A person jogging at $$3\ m/s$$ along a winding path
  • A car stopping at a stop sign
  • A cheetah running $$27\ m/s$$ east
  • A plane taking off
A particle $$X$$ moving with a constant velocity $$u$$ crosses a point O. At the same instant another particle $$F$$ starts from rest from O with a constant acceleration $$a$$. The maximum separation between them before they meet is
  • $$u^{2}/2a$$
  • $$u^{2}/a$$
  • $$u/2a$$
  • $$u/a$$
A particle initially starts from rest, travels a distance Y in the first two seconds and a distance of X in next two seconds, if the body is moving with constant acceleration then :
  • X = 2Y
  • X + Y = 4X
  • X + Y = 4Y
  • X = 3Y
Consider a train which can accelerate with an acceleration of $$20 {cm}/{{s}^{2}}$$ and slow down with deceleration of $$100 {cm}/{{s}^{2}}$$. Find the minimum time for the train to travel between the stations $$2.7 km$$ apart.
  • 0
  • 90
  • 100
  • 180
An aeroplane flies along a straight line from A to B with air speed $$V$$ and back again with the same air speed.If the distance between A and B is $$l$$ and a steady wind blows perpendicular to AB with speed $$u$$, the total time taken for the round trip is
  • $$\dfrac{2l}{\sqrt{V^{2}-u^{2}}}$$
  • $$\dfrac{2l}{\sqrt{V^{2}+u^{2}}}$$
  • $$\dfrac{l}{\sqrt{V^{2}-u^{2}}}$$
  • $$\dfrac{3l}{\sqrt{V^{2}-u^{2}}}$$
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