If the velocity of light c, gravitational constant G and Planck's constant h are chosen as fundamental units, the dimensions of length L in the new system is
[h1c1G-1]
[h1/2c1/2G-1/2]
[h1c-3G1]
[h1/2c-3/2G1/2]
A plate has a length 5 ± 0.1 cm and breadth 2 ± 0.01 cm. Then the area of the plate is
10 ± 0.1 cm2
10 ± 0.01 cm2
10 ± 0.001 cm2
10 ± 1 cm2
A ball hangs from a string inside a train moving along a horizontal straight track. The string is observed to incline towards the rear of the train making a constant small angle with the vertical. It shows that the train is
moving with a uniform acceleration
moving with a uniform velocity
moving with a uniform retardation
moving with an acceleration which is increasing uniformly
A particle moves along Y-axis in such a way that its y-coordinate varies with time t according to the relation y = 3 + 5t2 + 7t2. The initial velocity and acceleration of the particle are respectively
14 ms-1 , − 5 ms-2
19 ms-1 , − 9 ms-2
5 ms-1 , 14 ms-2
3 ms-1 , − 5 ms-2
An object travels north with a velocity of 10 ms-1 and then speeds up to a velocity of 25 ms-1 in 5 s. The acceleration of the object in these 5 s is
3 ms-1 in north direction
3 ms-2 in north direction
15 ms-2 in north direction
3 ms-2 in south direction
An automobile in travelling at 50 km/h, can be stopped at a distance of 40 m by applying brakes. If the same automobile is travelling at 90 km/h, all other conditions remaining same and assuming no skidding, the minimum stopping distance in metres is
72
92.5
102.6
129.6
A rifle shoots a bullet with a muzzle velocity of 500 ms-1 at a small target 50 m away. To hit the target the rifle must be aimed (take g = 10 ms-2)
exactly at the target
10 cm below the target
5 cm above the target
5 cm below the target
The centripetal acceleration of particle of mass m moving with a velocity v in a circular orbit of radius r is
v2/r along the radius, towards the centre
v2/r along the radius, away from the centre
mv2/r along the radius, away from the centre
mv2/r along the radius, towards the centre
An α-particle of mass m suffers one dimensional elastic collision with a nucleus of unknown mass. After the collision the α-particle is scattered directly backwards losing 75% of its kinetic energy. Then the mass of the nucleus is
m
2m
3m
C.
3m
While driving a car around a curve of 200 m radius, the driver notices that a simple pendulum hung to the roof of the car is making an angle of 15° to the horizontal. The speed of the car in km/h is
60.5
72.5
82.5
92.5