A stationary particle explodes into two particles of masses m_{1} and m_{2} which move in opposite directions with velocities v_{1} ad v_{2}. The ratio of their kinetic energies E_{1} / E_{2} is

(A)

1

(B)

(C)

(D)

Question-2

A body of mass m moving with velocity 3 km/h collides with a body of mass 2m at rest. Now the coalesced mass starts to move with a velocity

(A)

1 km/h

(B)

2 km/h

(C)

3 km/h

(D)

4 km/h

Question-3

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

(A)

5kg

(B)

7kg

(C)

17kg

(D)

3kg

Question-4

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

(A)

1 : 9

(B)

9 : 1

(C)

1 : 3

(D)

3 : 1

Question-5

300 J of work is done in sliding a 2kg block up an inclined plane of height 10 m. Taking g = 10 m/s^{2}, work done against friction is

(A)

200 J

(B)

100 J

(C)

zero

(D)

1000J

Question-6

A position dependent force F=(7–2x + 3x^{2}) N acts on a small body of mass 2 kg and displaces it from x = 0 to x = 5m.

Work done in joule is

(A)

35

(B)

70

(C)

135

(D)

270

Question-7

A particle of mass m_{1} is moving with a velocity v_{1} and another particle of mass m_{2} is moving with a velocity v_{2}. Both of them have the same momentum but their different kinetic energies are E_{1} and E_{2} respectively. If m_{1}> m_{2}, then

(A)

E_{1} < E_{2 }

(B)

(C)

E_{1} > E_{2 }

(D)

E_{1} = E_{2}

Question-8

A stone is thrown at an angle of 45^{o} to the horizontal with kinetic energy K. The kinetic energy at the highest point is

(A)

(B)

(C)

K

(D)

zero

Question-9

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

(A)

256 J

(B)

486 J

(C)

524 J

(D)

324 J

Question-10

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?

(A)

½ mv^{3 }

(B)

mv^{3 }

(C)

½ mv^{2 }

(D)

½ m^{2}v^{2}

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