In order to find the efficiency first we will find the Change in Potential energy of the small stone that robot picked up
First we will find the mass of the stone
As it is given that stone is spherical in shape so first we will find its volume



Now it is given that it's specific gravity is 10.8
So density of rock is

mass of the stone will be



now change in potential energy is given as

here
g = gravity on planet = 0.278 m/s^2
H = height lifted upwards = 15 cm


Now energy supplied by internal circuit of robot is given by

V = voltage supplied = 10 V
i = current = 1.83 mA
t = time = 12 s


Now efficiency is defined as the ratio of output work with given amount of energy used


so efficiency will be 23 %
The velocity of pin B after rod AB has rotated through 90* is vb = 3.2549 m/s.
<h3>What is Potential and Kinetic energy?</h3>
Potential energy is the energy that is stored in any item or system as a result of its location or component arrangement. The environment outside of the object or system, such as air or height, has no impact on it. In contrast, kinetic energy refers to the energy of moving particles inside a system or an item.
mass of rod, mab = 2.4kg
mass of rod, mbc = 4kg
conservation of energy


potential energy at position 1,

V1 = 2.5 * 9.81 * 0.18 + 4 * 9.81 * 0.18
V1 = 11.30112
kinetic energy T1 at position 1 is zero
potential energy at position 2 is zero
K.E at position 2,


= 1/3 *4 * (0.36)²
=0.10368kg m²

= 1/12 *4 * (0.6)²
=0.12kg m²
on putting the values in above equation we get,
T₂ = 1.0667vb²
0 + 11.30112 = 1.0667vb² + 0
vb = 3.2549 m/s
to learn more about Kinetic and potential energy go to - brainly.com/question/18963960
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The best and most correct answer among the choices provided by your question is the second choice or letter B.
<span>When the switch is closed, the current instantaneously becomes 1.</span>
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Circumference C=2πr
<span>C=2π(1.5x10^8)=9.42x10^8 </span>
<span>In 365 Days there are 8760hr </span>
<span>V=distance/time </span>
<span>V=(9.42x10^8)/8760=107534.2km/hr </span>