Two spherical shells one which is placed in air has constant charge Q; and the other which is placed in a medium of dielectric constant K has a charge Q; The ratio of forces between the shell is:
K : 1
1 : K
K2 : 1
1 : K2
A 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
Mass of a planet is 10 times that of earth and radius is 2 times that of earth. If at the earth, the escape velocity of a satellite is Ves(e), then escape. velocity at the planet is :
ves(e)
5ves(e)
2 ves(e)
10 ves(e)
A car and a container, moving with equal kinetic energies are stopped by applying a negative acceleration. Then
container will move less distance before being stopped
both will become stationary after moving some distance
car will move less distance before being stopped
none of the above
The mass of a solid sphere is 2 kg and radius is 10 cm. Sphere, tied to one end of 1 m long string, is rotated at a rate of 10 rad/sec. The rotational kinetic energy of sphere is :
121.4 J
18.5 J
15.2 J
22.0 J
A rocket is accelerated with speed v= 2, near earth surface and then it moves upward. At far distance from the earth surface, the speed of the rocket will
be:
(2-)
In the rotational motion, different particles of the body have :
both linear and angular velocities equal
linear velocities equal but different angular velocities
angular velocities equal but different linear velocities
both linear and angular velocity different
A car covers 2/5 of a certain distance with speed v1 and rest 3/5 part with velocity v2. The average speed of the car is :
B.
Let total distance covered = s
t1= and t2 =
Average speed =
v =
or v =
Hence, v =
The momentum of two masses m1 and m2 are same. The ratio of their kinetic energies E1 and E2 is
m1 : m2
m2 : m1
m12 : m22
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