CBSE
Multiple Choice QuestionsA force F acting on an object varies with distance x as shown in the figure. The force is in N and x in m. The work done by the force in moving the object from x = 0 to x = 6 m is
13.5 J
10 J
15 J
20 J
Assertion: The apparent weight of a body in an elevator moving with some downward acceleration is less than the actual weight of a body.
Reason: The part of the weight is spent in producing downward acceleration, when body
is in elevator.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false.
If both assertion and reason are false.
A body is moved along a straight line by a machine delivering constant power. The distance travelled by the body in time t is proportional to
t1/2
t
t3/2
t2
The voltage of clouds is 4 x 10 volt with respect to ground. In a lightening strike lasting 100 msec, a charge of 4 coulombs is delivered to the ground. The power of the lightning strike is
160 MW
80 MW
20 MW
500 MW
P, Q and R are three coplanar forces acting at a point and are in equilibrium. Given: P = 1.9318 kg wt [sin θ1 = 0.9659], the value of R (in kg wt) is
0.9659
2
1
1/2
If a solid sphere of mass 1 kg and radius 0.1 m rolls without slipping at a uniform velocity of I m/s along a straight line on a horizontal floor, the kinetic energy is
J
J
J
1 J
For inelastic collision between two spherical rigid bodies
the total kinetic energy is conserved
the total potential energy is conserved
the linear momentum is not conserved
the linear momentum is conserved
A block of mass 10 kg is moving in x-direction with a constant speed of 10 m/sec. It is subjected to a retarding force F = -0.1 x joule/meter during its travel from x = 20 meter to x = 30 meter. Its final kinetic energy will be
475 joule
450 joule
275 joule
250 joule
Assertion: If momentum of a body increase by 50%, its kinetic energy will increase by 125 %.
Result: Kinetic energy is proportional to square of velocity.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
A person used force (F), shown in figure to move a load with constant velocity on surface. Identify the correct surface profile.
