Answer:
The time taken by the brick to hit the ground, t = 0.84 s
Explanation:
Given that,
A brick falls from a height, h = 3.42 m
The initial velocity of the brick is zero.
Since the brick is under free-falling. The time equation of a free-falling body when the displacement is given is
t = 
where,
h - height from surface in meters
g - acceleration due to gravity
on substituting the values in the above equation,
t = 
= 0.84 s
Hence, time taken by the brick to hit the ground is t = 0.84 s
None of the above. 1 mL= 1 cubic centimeter
mm is the smallest.
Ans: Time <span>taken by a pulse to travel from one support to the other
= 0.348s</span>
Explanation:First you need to find out the speed of the wave.
Since
Speed = v =

Where
T = Tension in the cord = 150N
μ = Mass per unit length = mass/Length = 0.65/28 = 0.0232 kg/m
So
v =

= 80.41 m/s
Now the time-taken by the wave = t = Length/speed = 28/80.41=
0.348s