Answer:
Length of copper wire, l = 785 meters
Explanation:
Given that,
Resistance of the copper wire, R = 0.172 ohms
Area of cross section, 
Resistivity of copper, 
The resistance of a wire is given by :



l = 785 meters
So, the length of the copper wire is 785 meters. Hence, this is the required solution.
Answer:0.2mm
Explanation:
The length of one VSD=8/10=0.8mm
The least count of the instrument is the difference between the length of one MSD and length of one VSD
The length of inebriated MSD=1mm
Therefore,
The least count=1-0.8=0.2mm
Answer:
(a). The initial velocity is 28.58m/s
(b). The speed when touching the ground is 33.3m/s.
Explanation:
The equations governing the position of the projectile are


where
is the initial velocity.
(a).
When the projectile hits the 50m mark,
; therefore,

solving for
we get:

Thus, the projectile must hit the 50m mark in 1.75s, and this condition demands from equation (1) that

which gives

(b).
The horizontal velocity remains unchanged just before the projectile touches the ground because gravity acts only along the vertical direction; therefore,

the vertical component of the velocity is

which gives a speed
of


<span>x=((12.3/100)m)cos[(1.26s^−1)t]
v= dx/dt = -</span><span>((12.3/100)*1.26)sin[(1.26s^−1)t]
v=</span>-((12.3/100)*1.26)sin[(1.26s^−1)t]=-((12.3/100)*1.26)sin[(1.26s^−1)*(0.815)]
v=<span>
<span>-0.13261622 m/s
</span></span>the object moving at 0.13 m/s <span>at time t=0.815 s</span>