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Kinematics-2D

118 Questions Start Errorless Test
All Exams Allen Advance Errorless
Basic Level Q76 Errorless 7. Energy MCQ
A cricket ball is hit at $30^{\circ}$ with the horizontal with kinetic energy $K$ . The kinetic energy at the highest point is
A.
Zero
B.
$K / 4$
C.
$K / 2$
D.
$3K / 4$
Basic Level Q77 Errorless 7. Energy MCQ
Two balls are projected, one vertically up and the other at an angle of $30^{\circ}$ to the horizontal, with the same initial speed. The potential energy at the highest point will be in the ratio
A.
$3:4$
B.
$4:3$
C.
$4:1$
D.
$1:4$
Basic Level Q78 Errorless 7. Energy MCQ
In the above problem the ratio of kinetic energies of these balls at the highest point is
A.
$4:3$
B.
$3:4$
C.
$\infty$
D.
o
Basic Level Q79 Errorless 7. Energy MCQ
A body is projected such that the K.E. at the topmost position is half of the initial K.E. What is its angle of projection with the horizontal
A.
$30^{\circ}$
B.
$60^{\circ}$
C.
$75^{\circ}$
D.
$45^{\circ}$
Basic Level Q80 Errorless 7. Energy MCQ
A body is thrown with initial kinetic energy 100J at an angle $\theta^{\circ}$ to the horizontal. If its kinetic energy at the top is 25J, then the angle of projection is
A.
$30^{\circ}$
B.
$45^{\circ}$
C.
$60^{\circ}$
D.
$90^{\circ}$
Basic Level Q81 Errorless 8. Angular Displacement MCQ
A particle moves along a circular path of radius $r$ with uniform speed $v$ . The angle described by the particle in one second is given by
A.
$vr^{-1}$
B.
$v^{-1}r$
C.
$vr^{-2}$
D.
$v^2 r$
Basic Level Q82 Errorless 9. Angular Velocity MCQ
The angular velocity of earth about its axis of rotation is
A.
$2\pi/(60 \times 60 \times 24)$ rad/sec
B.
$2\pi/(60 \times 60)$ rad/sec
C.
$2\pi/60$ rad/sec
D.
$2\pi/(365 \times 24 \times 60 \times 60)$ rad/sec
Basic Level Q83 Errorless 9. Angular Velocity MCQ
The ratio of the angular velocities of rotational motion of earth round the sun and spinning motion about its own axis is
A.
1/12
B.
1/24
C.
1/365
D.
1/3600
Basic Level Q84 Errorless 9. Angular Velocity MCQ
The ratio of an angular speed of hours hand and seconds hand of a clock is 210 Motion In Two Dimension
A.
1 : 1
B.
1 : 60
C.
1 : 720
D.
3600 : 1
Advance Level Q85 Errorless 9. Angular Velocity MCQ
A racing car is travelling along a track at a constant speed of 40 m/s. A T.V. camera men is recording the event from a distance of 30m directly away from the track as shown in figure. In order to keep the car under view in the position shown, the angular speed with which the camera sh
A.
4/3 rad/sec
B.
3/4 rad/sec
C.
8/3 $\sqrt{3}$ rad/sec
D.
1 rad/sec
Advance Level Q86 Errorless 9. Angular Velocity MCQ
A particle is moving along a circular path with angular speed $\omega$ about the axis passing through the centre. What will be its angular speed about a point on the other end of the diameter through the instantaneous position of the particle
A.
$2\omega$
B.
$\omega$
C.
$\omega/2$
D.
$\omega/4$
Basic Level Q87 Errorless 2. Velocity MCQ
The linear velocity of a point on the equator is nearly (radius of the earth is 6400 km)
A.
800 km/hr
B.
1600 km/hr
C.
3200 km/hr
D.
6400 km/hr
Basic Level Q88 Errorless 2. Velocity MCQ
The second's hand of a watch has length 6 cm. Speed of end point and magnitude of difference of velocities at two perpendicular positions will be
A.
6.28 and 0 mm/s
B.
8.88 and 4.44 mm/s
C.
8.88 and 6.28 mm/s
D.
6.28 and 8.88 mm/s
Advance Level Q89 Errorless 2. Velocity MCQ
An aeroplane is moving in a horizontal circle with a uniform speed of 141 km/hr. Change in its velocity in one fourth revolution, from its initial direction will be
A.
100 km/hr at an angle of $90^{\circ}$
B.
141 km/hr at an angle of $135^{\circ}$
C.
200 km/hr at an angle of $135^{\circ}$
D.
Zero
Basic Level Q90 Errorless 10. Angular Accelerations MCQ
The linear and angular acceleration of a particle are $10 \, m/sec^{2}$ and $5 \, rad/sec^{2}$ respectively it will be at a distance from the axis of rotation
A.
50 m
B.
$1/2 \, m$
C.
1 m
D.
2 m
Basic Level Q91 Errorless 10. Angular Accelerations MCQ
On applying brakes the angular velocity of a flywheel reduces from 900 cycles/min to 720 cycles/min in 6 seconds. Its angular retardation in $rad/s^2$ will be
A.
$\pi/3$
B.
$\pi$
C.
$2\pi/3$
D.
$2\pi$
Advance Level Q92 Errorless 10. Angular Accelerations MCQ
A particle is moving in a circular path with velocity varying with time as $v = 1.5 t^{2} + 2t$ . If 2cm the radius of circular path, the angular acceleration at t = 2 sec will be
A.
$4 rad/sec^{2}$
B.
$40 rad/sec^{2}$
C.
$400 rad/sec^{2}$
D.
$0.4 rad/sec^{2}$
Basic Level Q93 Errorless 11. Centripetal Acceleration MCQ
A stone, tied at the end of a string 80 cm long, is whirled in a horizontal circle with a constant speed. If the stone makes 14 revolutions in 25 sec, what is the magnitude of acceleration of the stone
A.
$680 \, cm/s^{2}$
B.
$720 \, cm/s^{2}$
C.
$860 \, cm/s^{2}$
D.
$990 \, cm/s^{2}$
Basic Level Q94 Errorless 11. Centripetal Acceleration MCQ
What happens to the centripetal acceleration of a revolving body if you double the orbital speed v and half the angular velocity $\omega$
A.
The centripetal acceleration remains unchanged
B.
The centripetal acceleration is halved
C.
The centripetal acceleration is doubled
D.
The centripetal acceleration is quadrupled
Basic Level Q95 Errorless 11. Centripetal Acceleration MCQ
The mean distance of the moon from the earth is $3.84 \times 10^{8} m$ . The moon makes one revolution round the earth in $2.34 \times 10^{6}$ sec. The acceleration of the moon towards the earth is
A.
$2.73 \times 10^{-3} m/s^{2}$
B.
$2.73 \times 10^{-2} m/s^{2}$
C.
$0.273 m/s^{2}$
D.
$2.73 \times 10^{-4} m/s^{2}$
Advance Level Q96 Errorless 11. Centripetal Acceleration MCQ
An astronaut is rotating in a rotor of radius $4m$ . If he can withstand maximum acceleration of $10g$ , the maximum permissible frequency of rotor will be
A.
$\frac{\pi}{5} Hz$
B.
$\frac{2\pi}{5} Hz$
C.
$\frac{5\pi}{5} Hz$
D.
$\frac{5}{2\pi} Hz$
Q97 Errorless 12. Centripetal and Centrifugal Force MCQ
Two masses M and m are attached to a vertical axis by weightless threads of combined length L. They are set in rotational motion in a horizontal plane about this axis with constant angular velocity $\omega$ . If the tensions in the threads are the same during motion, the distance of M from the axis is
A.
$\frac{Ml}{M+m}$
B.
$\frac{ml}{M+m}$
C.
$\frac{M+m}{M}l$
D.
$\frac{M+m}{m}l$
Q98 Errorless 12. Centripetal and Centrifugal Force MCQ
In the Bohr model of a hydrogen atom, the centripetal force is furnished by the coulomb attraction between the proton and the electron. If $a_0$ is the radius of the ground state orbit, $m$ is the mass, $e$ is the charge on the electron and $\varepsilon_0$ is the vacuum permittivity, then speed of the electron is
A.
$\sqrt{\frac{\varepsilon_0a_0m}{e}}$
B.
$\frac{e}{\sqrt{\varepsilon_0a_0m}}$
C.
$\frac{\sqrt{4\pi\varepsilon_0a_0m}}{e}$
D.
$\frac{e}{\sqrt{4\pi\varepsilon_0a_0m}}$
Q99 Errorless 12. Centripetal and Centrifugal Force MCQ
A rubber band of length l has a stone of mass m tied to its one end. It is whirled with speed v so that the stone describes a horizontal circular path. The tension T in the rubber band is
A.
Zero
B.
$mv^{2}/l$
C.
$>(mv^{2})/l$
D.
$
Q100 Errorless 12. Centripetal and Centrifugal Force MCQ
A particle of mass m is executing uniform circular motion on a path of radius r. If p is the magnitude of its linear momentum. The radial force acting on the particle is
A.
pmr
B.
$\frac{rm}{p}$
C.
$\frac{mp^{2}}{r}$
D.
$\frac{p^{2}}{rm}$