CBSE
Multiple Choice QuestionsA block of mass 1 kg is placed on the wall under a force F. If coefficient of friction () is 0.5, then minimum value of force applied is :
9.8 N
49 N
19.6 N
1.96 N
A force of 49 newtons is just able to move a block of wood weighing 10 kg-on a rough horizontal surface. Its coefficient of friction is :
1
0.7
0.5
zero
A 1 kg stone at the end of 1 m long string is whirled in a vertical circle at constant speed of 4 m/s. The tension in the string is 6 N, when the stone is a
top of the circle
bottom of the circle
halfway down
None of the above
Two bodies having masses m1 = 40g and m2 = 60 g are attached to the ends of a string of negligible mass and suspended from a massless pulley. The acceleration of the bodies is:
1 m/s2
2 m/s2
0.4 m/s2
4 m/s2
A car is moving with speed 30 m/s on a circular path of radius 500 m. If its speed is increasing at a rate of 5m/s2, then resultant acceleration at that instant is
6.83 m/s2
8 m/s2
5.31 m/s2
4 m/s2
Two bodies of mass m and 4m have equal kinetic energy. What is the ratio of their momentum?
1 : 4
1 : 2
1 : 1
2 : 1
A block of mass 2 kg is kept on the floor. The coefficient of static friction is 0.4. If a force F of 2.5 N is applied on the block as shown in the figure, the frictional force between the block and the floor will be
2.5 N
5 N
7.84 N
10 N
A body takes time t to reach the bottom of an inclined plane of angle 0 with the horizontal. If the plane is made rough, time taken now is 2t. The coefficient of friction of the rough surface is:
A block is moving up an inclined plane of inclination 60° with a velocity of 20 m/s and stops after 2 s. If g = 20 m/s2 then the approximate value of the coefficient of friction is :
3
3.3
0.27
0.33
A particle is moving in a circle with uniform speed v. In moving from a point to another diametrically opposite point :
the momentum changes by mv
the momentum changes by 2mv
the kinetic energy changes by 1/2 mv2
the kinetic energy changes by mv2
