An object start sliding on a frictionless inclined plane and from same height another object start falling freely.
both will reach with same speed
both will reach with same acceleration
both will reach in same time
None of the above
A boy on a cycle pedals around a circle of 20 metres radius at a speed of 20 m/s. The combined mass of the body and the cycle makes with the vertical so that it may not fall is (g = 9.8 m/s2 )
60.25o
63.90o
26.12o
30.00o
A coin is dropped in a lift. It takes time t1 to reach the floor when lift is stationary. It takes time t2 when lift is moving up with constant acceleration. Then,
t1 ≥ t2
t2 > t1
t1 = t2
t1 >> t2
The engine of a jet aircraft applies a thrown force of 105 N during take off and causes the plane to attain a velocity of 1 km/s in 10 s. The mass of the plane is
102 kg
103 kg
104 kg
105 kg
A stone is weighing 1 kg and sliding on ice with a velocity of 2 m/s is stopped by friction in 10 s. The force of friction (assuming it to be constant) will be
- 20 N
-0.2 N
0.2 N
20 N
The potential energy of a body is given by U = A - Bx2 (where x is the displacement ) The magnitude of force acting on the particle is
constant
proportional to x
proportional to x2
inversely proportional to x
When a ceiling fan is switched on, it makes 10 revolution in the first 3 s. Assuming a uniform angular acceleration, how many rotation it will make in the next 3 s
10
20
30
40
The cylindrical tube of a spray pump has a cross-section of 8 cm2 , one end of which has 40 fine holes each of area 10-8 m2. If the liquid flows inside the tube with a speed of 0.15 m min-1 the speed with which the liquid is ejected through the holes is
50 m/s
5 m/s
0.05 m/s
0.5 m/s
B.
5 m/s
One of the fundamental principles used in the analysis of uniform flow is known as continuity of flow. This principle is derived from the fact that mass is always conserved in fluid systems regardless of the pipeline complexity or direction of flow.
According to the equation of continuity,
Q = A1 V1 = A2 V2
a v = constant ... (i)
Where Q is the volumetric flow rate
A is the cross-sectional area of flow
V is the mean velocity
Area of cross secrction of the spray pump,
a1 = 8 cm2 = 8 × 10-4 m2
number of holes n = 40
v1 = 0.15 m min-1 =
∴ For tube,
= a1 v1
For holes,
= a2 v2
According to law of continuity from equation (i)
∴ a2 v2 = a1 v1
∴ 40 × 10-8 × v =
⇒ v =
⇒ v = 5 m/s
In Young's double slit experiment with sodium vapour lamp of wavelength 589 nm and the slits 0.589 mm apart, the half angular width of the central maximum is
sin-1 (0.01)
sin-1 (0.0001)
sin-1 (0.001)
sin-1 (0.1)
Horizontal tube of non-uniform cross-section has radii of 0.1 m and 0.05 m respectively at M and N. For a streamline flow of liquid, the rate of liquid flow is
changing continuously with time
greater at M than at N
greater at N than at M
same at M and N