A water film is made between two 10 cm long straight wires and at a distance of 0.5 cm. If distance between the wires is increased by 1 mm, then work done will be (T = 7.2 x 10-2N/m)
7.22 × 10-6 J
1.44 × 10-5 J
2.88 × 10-5 J
5.76 × 10-5 J
The average kinetic energy of a hydrogen gas molecule at NTP will be (Boltzmann's constant k = 138 x 10-23 J/K)
0.186 × 10-20 J
0.372 × 10-20 J
0.56 × 10-20 J
5.6 × 10-20 J
The height of a water fall is 84 m. Assuming that the entire kinetic energy of falling water is converted into heat, the rise in temperature of the water will be
0.196°C
1.960°C
0.96°C
0.0196°C
If a body loses half of its velocity on penetrating 3 cm in a wooden block then how much will it penetrate more before coming to rest?
1 cm
2 cm
3 cm
4 cm
A.
1 cm
Let initial velocity of body at point A is v. AB is 3 cm
v2 = u2 − 2as
Let an penetrating 3 cm in a wooden block the body moves x distance from B to C.
According to the question
u = and v = 0
∴ (0)2 =
x = 1
The minimum velocity (in ms-1) with which a car driver must traverse a flat curve of radius 150 m and coefficient of friction to avoid skidding is
60
30
15
25
A steel ball is dropped from a height h and it makes a perfectly elastic collision with a horizontal plane. Following its initial release, it will make periodic motion with frequency
If the earth is treated as a sphere of radius R and mass M, its angular momentum about the axis of rotation with time period T is
A child swinging on a swing in sitting position, stands up, then the time period of swing will
increase
decrease
remain same
increase if the child is long and decrease if the child is short
A mass of 10 g moving horizontally with a velocity of 100 cm/s strikes a pendulum bob of mass 10 g. The two masses stick together. The maximum height reached by the system now is (g = 10 m/s2)
zero
5 cm
2.5 cm
1.25 cm
A particle of mass 10 g is executing simple harmonic motion with an amplitude of 0.5 m and periodic time of (/ 5) second. The maximum value of the force acting on the particle is
25 N
5 N
2.5 N
0.5 N