Send is being dropped on a conveyor belt at the rate of M kg/s. The force necessary to keep the belt moving with a constant velocity of v m/s will be
Mv Newton
2Mv Newton
zero
A ball of mass 2 kg and another of mass 4kg are dropped together from a 60 ft tall building. After a fall of 30 ft each towards earth, their respective kinetic energies will be in the ratio of
1 : 4
1 : 2
A stationary particle explodes into two particles of masses m1 and m2 which move in opposite directions with velocities v1 ad v2. The ratio of their kinetic energies E1 / E2 is
1
A body of mass 3 kg is under a constant force which causes a displacement s in metre in it, give by the relation
where t is in second. Work done by the force is 2s is
300 J of work is done in sliding a 2kg block up an inclined plane of height 10 m. Taking g = 10 m/s2, work done against friction is
200 J
100 J
1000J
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)
20 J
30 J
40 J
10 J.
How much water a pump of 2 k W can raise in one minute to a height of 10 m.? (Take g = m/s2)
1000 L
1200 L
100 L
2000 L
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
E1 < E2
E1 > E2
E1 = E2
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
570 mJ
450 mJ
490 mJ
528 mJ
An engine pumps water continuously through a hose. Water leaves the hose with a velocity v and m is the mass per unit length of water jet. What is the rate at which kinetic energy is imparted to water?
½ mv3
mv3
½ mv2
½ m2v2