The force needed to overcome sliding friction is more than the force needed to overcome rolling friction or static or even fluid
If you were to sit a hot cup of water out side it would frezze faster
Answer: False
Explanation: In order to explain this problem we have to use the Faraday law, which say
dФm/dt=-ε it means that the variation of the magnetic field flux with time is equal to the emf ( electromotive force). In our case the magnetic flux is constant then there is not a emf induced in a wire closed loop.
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 %
V = t^2 - 9t + 18
position, s
s = t^3 /3 - 4.5t^2 +18t + C
t = 0, s = 1 => 1=C => s = t^3/3 -4.5t^2 + 18t + 1
Average velocity: distance / time
distance: t = 8 => s = 8^3 / 3 - 4.5 (8)^2 + 18(8) + 1 = 27.67 m
Average velocity = 27.67 / 8 = 3.46 m/s
t = 5 s
v = t^2 - 9t + 18 = 5^2 - 9(5) + 18 = -2 m/s
speed = |-2| m/s = 2 m/s
Moving right
V > 0 => t^2 - 9t + 18 > 0
(t - 6)(t - 3) > 0
=> t > 6 and t > 3 => t > 6 s => Interval (6,8)
=> t < 6 and t <3 => t <3 s => interval (0,3)
Going faster and slowing dowm
acceleration, a = v' = 2t - 9
a > 0 => 2t - 9 > 0 => 2t > 9 => t > 4.5 s
Then, going faster in the interval (4.5 , 8) and slowing down in (0, 4.5)
