If the water falls from a dam into a turbine wheel 19.6 m below, then the velocity of water at the turbine is (g = 9.8 m/s²) 

(1) 9.8 m/s

(2) 19.6 m/s

(3) 39.2 m/s

(4) 98.0 m/s

Two identical cylindrical vessels with their bases at the same level each contain a liquid of density; $\rho$. The height of the liquid in one vessel is h₁ and that in the other vessel is h₂ $\left(h_1>h_2\right)$.The area of either base is A. The work done by gravity in equalizing the levels when the two vessels are connected is :

(1) $(h_1-h_2)g\rho$

(2) $(h_1-h_2)gA\rho$

(3) $\frac{1}{2}{(h_1-h_2)}^{2}gA\rho$

(4) $\frac{1}{4}{(h_1-h_2)}^{2}gA\rho$

If the increase in the kinetic energy of a body is 21%, then the increase in the momentum will be:
1. 22%
2. 44%
3. 10%
4. 300%

If a body of mass 200 g falls from a height 200 m and its total P.E. is converted into K.E. at the point of contact of the body with earth surface, then what is the decrease in P.E. of the body at the contact (g = 10 m/s²) 

(1) 200 J

(2) 400 J

(3) 600 J

(4) 900 J

If momentum is increased by \(20\text{%}\) then kinetic energy increases by: 
1. \(44\text{%}\)
2. \(55\text{%}\)
3. \(66\text{%}\)
4. \(77\text{%}\)

The kinetic energy of a body of mass 2 kg and momentum of 2 Ns is 

(1) 1 J

(2) 2 J

(3) 3 J

(4) 4 J

The decrease in the potential energy of a ball of mass 20 kg which falls from a height of 50 cm is 

(1) 968 J

(2) 98 J

(3) 1980 J

(4) None of these

A 0.5 kg ball is thrown up with an initial speed 14 m/s and reaches a maximum height of 8.0m. How much energy is dissipated by air drag acting on the ball during the ascent 

(1) 19.6 Joule

(2) 4.9 Joule

(3) 10 Joule

(4) 9.8 Joule

An ice cream has a marked value of 700 kcal. How many kilowatt- hour of energy will it deliver to the body as it is digested 

(1) 0.81 kWh

(2) 0.90 kWh

(3) 1.11 kWh

(4) 0.71 kWh

A running man has half the kinetic energy of that of a boy of half of his mass. The man speeds up by 1m/s so as to have same K.E. as that of the boy. The original speed of the man will be 

(1) $\sqrt{2}m/s$

(2) $(\sqrt{2}-1)m/s$

(3) $\frac{1}{(\sqrt{2}-1)}m/s$

(4) $\frac{1}{\sqrt{2}}m/s$