# RAC ISRO 2015

1. A body is resting on a plane inclined at angle of 30° to horizontal. What force would be required to slide it down, if the coefficient of friction between body and plane is 0.3?

(a) 5 kg

(b) 1 kg

(c) zero

(d) 0.5 kg

2. Compression members tend to buckle in the direction of

(c) perpendicular to axis of load

(d) minimum crosssection

3. A fluid jet discharging from 150 mm diameter orifice has a diameter of 100 mm at its vena contracta. The coefficient of contraction is

(a) 0.44

(b) 1.24

(c) 0.24

(d) 0.64

4. The escape velocity on the surface of the earth is

(a) 11.2 km/sec

(b) 1 km/sec

(c) 3.km/sec

(d) 8.8 km/sec

5. The heat to be supplied to a Carnot engine operating between 800 and 400 K and producing 100 kJ of work, is

(a) 100 kJ

(b) 200 kJ

(c) 300 kJ

(d) 400 kJ

6. A piece of wood having weight of 10 kg floats in water with 60% of its volume under the liquid. Determine the specific Gravity of wood.

(a) 0.6

(b) 0.83

(c) 0.4

(d) 0.3

7. If all the dimension of a prismatic bar be increased in the ratio of k:1, then maximum stress produced in the bar due to its own weight will increase in the following ratio

(a) 1 : k

(b) k2 : 1

(c) k3 : 1

(d) k : 1

8. A house requires 60M cal/hr in winter for heating. Heat pump absorbs heat from cold air outside and requires 8M cal/hr of work. The COP will be

(a) 0.75

(b) 7.5

(c) 6.5

(d) 10

9. A body moves, from rest with a constant acceleration of 5 m per sec2. The distance covered in 10 sec is most nearly

(a) 200 m

(b) 300 m

(c) 250 m

(d) 500 m

10. A cold storage plant of 20 tonne of refrigerator capacity operates between 200 and 300 k. The power required to run the plant if the plant has half COP of a Carnot cycle (Tonne of refrigerator = 3.5 kW) is

(a) 50 kW

(b) 60 kW

(c) 70 kW

(d) 80 kW