Answer:
Option D
Explanation:
The work done can be given by the mechanical energy used to do work, i.e., Kinetic energy and potential energy provided to do the work.
In all the cases, except option D, the energy provided to do the useful work is not zero and hence work done is not zero.
In option D, the box is being pulled with constant velocity, making the acceleration zero and thus Kinetic energy of the system is zero. Hence work done in this case is zero.
Answer:
A conservative force is a force with the property that the total work done in moving a particle between two points is independent of the path taken Equivalently if a particle travels in a closed loop the total work done by a conservative force is zero
Explanation:
Answer:
d. It increases numerical aperture and maintains a uniform light speed.
Explanation:
In optical microscopes, various immersion mediums are used to improve or enhance the resolution. Immersion oils like cedar and Leica oils are one of those mediums which are used to improve resolution by increasing the numerical aperture and keeping the speed of light uniform.
Answer:
14 m/s
Explanation:
u = 0, h = 10 m, g = 9.8 m/s^2
Use third equation of motion
v^2 = u^2 + 2 g h
Here, v be the velocity of ball as it just strikes with the ground
v^2 = 0 + 2 x 9.8 x 10
v^2 = 196
v = 14 m/s
