CBSE
A particle rests on the top of a hemisphere of radius R. Find the smallest horizontal velocity that must be imparted to the particle, if it is to leave the hemisphere without sliding down it.
Two springs of force constant 1000 N/m and 2000 N/m are stretched by same, force. The ratio of their respective potential energies is
2 : 1
1 : 2
4 : 1
1 : 4
Two bodies of masses m and 2 m have equal kinetic energies. The ratio of their linear momenta is :
1
1/2
1/
2
A body of mass m is moving towards the east and another body of equal mass is moving towards the north. If after collision both stick together, their speed after collision would be :
v
v/2
A ball of mass m elastically collides with a wall with velocity 'v', then change in its momentum is equal to :
2m
2mv
+ 8mv
Zero
Hailstone at 0°C falls from a height of 1 km on an insulating surface converting the whole of its kinetic energy into heat. What part of it will melt? (g = 10 m/s2)
1/33
1/8
All of it will melt
A ball falling freely from a height of 4.9 m/s hits a horizontal surface. If e = ¾, then the ball will hit the surface second time after:
0.5 s
1.5 s
3.5 s
3.4 s
Two bodies A and B have masses M and m respectively, where M > m and they are at a distance d apart. Equal force is applied to them so that they approach each other. The position where they hit each other is
nearer to B
nearer to A
at equal distance from A and B
Cannot be predicted
When a man increases his speed by 2 m/s, he finds that his kinetic energy is doubled, the original speed of the man is :
4.5 m/s
none of these
A body of mass 1 kg is moving in a vertical circular path of radius 1 m. The difference between the kinetic energies at its highest and lowest position is :
20 J
10 J
10( - 1) J