An explosion blows a rock into three parts. Two parts go off at the right angles to each other. These two are, 1kg first part moving with a velocity of 12 ms^-1 and 2kg second part moving with  a velocity of 8ms^-1. If the third part flies off with a velocity of 4ms^-1, its mass would be 

How much water  a pump of 2 k W can raise in one minute to a height of 10 m.? (Take g = m/s²)

A particle of mass m₁ is moving with a velocity v₁ and another particle of mass m₂ is moving with a velocity v₂. Both of them have the same momentum but their different kinetic energies are E₁ and E₂ respectively. If m₁> m₂, then

Two masses 1g and 9g are moving with equal kinetic energies. The ratio of the magnitudes of their respective linear momenta is

A force acts on a 3.0 g particle in such a way that the position of the particle as a function of time is given by  x = 3 t – 4 t ² +  t ^3, where x is in meter and  t  in second. The work done during the first 4 s is 

A child swinging  a swing. Minimum and maximum heights of swing from earth’s  surface are 0.75 m and 2m respectively. The maximum velocity of this swing is 

The identical balls A and B moving with velocities + 0.5 m/s and -0.3 m/s respectively collide head on elastically. The velocity of the balls A and B after collision will be respectively

A bomb of mass 30kg at rest explodes into two pieces of masses 18kg ad 12kg. The velocity of 18kg mass is 6ms^-1. The kinetic energy of the other mass is 

Two bodies with kinetic energies in the ratio 4 : 1 are moving with equal linear momentum. The ratio of their masses is

A body of mass 1kg is thrown upward with a velocity 20 ms^-1.It momentarily comes to rest after attaining a height of 18m. How much energy is lost due to air friction ? ( g = 10 ms^-2)