B) A stone is dropped from the roof of a four storey building. The height of each storey is 4.9m . Taking g =9.8m/s2 , calculate the velocity with
which the stone will hit the ground.

9.8m/s

Explanation:

Given,

distance of each storey () = 4.9m

distance of 4 storey (s) = 19.6m

acceleration due to gravity (g) = 9.8 m/s^2

time given (t) = ?

velocity = (?)

initial velocity (u) = 0 {due to fall from certain height}

using formula,

s = ut + 1÷2at^2

s = 0 + 9.8÷2×t^2

19.6×2÷9.8 = t^2

4 = t^2

t = 2

now,

velocity ( v )= s ÷ t

v = 19.6 ÷ 2

v = 9.8 m/s

ans

science is a systematic and logical approach to discovering how things in the universe work. true to this definition, science aims for measurable results through testing and analysis. science is based on fact, not opinion or preferences. the process of science is designed to challenge ideas through research.

explanation:

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation: