A body starts rolling down on an inclined plane, the top half of which is perfectly smooth and lower half is rough. The angle of the plane being 30°, if the body is brought to rest just when it reaches the bottom, then the ratio of force of friction and weight of the body is
1 : 1
1 : 2
2 : 1
3 : 2
A particle is projected upwards from the surface of the earth (of radius R) with a KE equal to half the minimum value needed for it to escape. To what height (h) does it rise above the surface of the earth
R
2R
(R)1/2
In figure shown below, a particle is travelling counter clockwise in circle of radius 10 m. The acceleration vector indicated at a specific time. Find the value of 'v' at this time.
10 m/s
15 m/s
20 m/s
7 m/s
A lift of mass 1000 kg is descending with a speed of 6 ms-1 . Suddenly the cable of the lift begins to slip and it falls with a constant acceleration a = m / s2 . What is the kinetic energy of the lift after falling a distance 15 m ?
121.3 kJ
155.6 kJ
147.4 kJ
134.1 kJ
A solid sphere rolls without slipping and presses a spring of spring constant k as shown in figure. Then, the compression in the spring will be
A pendulum made of a uniform wire of cross-sectional area A has time period T. When an additional mass M is added to its bob, the time period changes to Tm . If the Young's modulus of the material is Y, then is equal to
Work of 146 kJ is performed in order to compress one kilo mole of a gas adiabatically and in this process the temperature ofthe gas increases by 7° C. The gas is (R = 8.3 J mol-1 K-1 )
diatomic
triatomic
a mixture of monoatomic and diatomic
monoatomic
Which of the following graphs represents resonance for low damping ?
graph (1)
graph (2)
graph (3)
None of these
A bat emitting an ultrasonic wave of frequency 2 x 104 Hz flies at a speed of 6 m/s between two parallel walls. The beat frequency between the two frequencies heard
by the bat is (Given, speed of sound is 330 m/s)
600 Hz
800 Hz
900 Hz
1300 Hz
D.
1300 Hz
Frequency received by bat after reflection from wall 1
Frequency received by bat after reflection from wall 2
Consider an ideal gas confined in an isolated closed chamber. As the gas undergoes an adiabatic expansion, the average time of collision between molecules increases to Vq , where V is the volume of the gas. The value of q is