The two-second rule.
It is a common guideline to follow while driving.
It means that any given driver should be AT LEAST two seconds behind any vehicle that is driving in front of his vehicle. It might apply for any kind of vehicle.
Answer:
a) 
b) x = 4.47 cm
c) 
d) x = 1.48 cm
Explanation:
a) The center of mass is equal to:

Where m is the mass of beads and x is the distances, if x₁ = d₁, x₂ = d₂ and x₃ = d₃

b) If
m₁ = 23g
m₂ = 15 g
m₃ = 58 g
d₁ = 1.1 cm
d₂ = 1.9 cm
d₃ = 3.2 cm

c) The center of the mass of the beads realtive to the center of bead is:

d) 
<h2>
Answer:</h2>
143μH
<h2>
Explanation:</h2>
The inductance (L) of a coil wire (e.g solenoid) is given by;
L = μ₀N²A / l --------------(i)
Where;
l = the length of the solenoid
A = cross-sectional area of the solenoid
N= number of turns of the solenoid
μ₀ = permeability of free space = 4π x 10⁻⁷ N/A²
<em>From the question;</em>
N = 183 turns
l = 2.09cm = 0.0209m
diameter, d = 9.49mm = 0.00949m
<em>But;</em>
A = π d² / 4 [Take π = 3.142 and substitute d = 0.00949m]
A = 3.142 x 0.00949² / 4
A = 7.1 x 10⁻⁵m²
<em>Substitute these values into equation (i) as follows;</em>
L = 4π x 10⁻⁷ x 183² x 7.1 x 10⁻⁵ / 0.0209 [Take π = 3.142]
L = 4(3.142) x 10⁻⁷ x 183² x 7.1 x 10⁻⁵ / 0.0209
L = 143 x 10⁻⁶ H
L = 143 μH
Therefore the inductance in microhenrys of the Tarik's solenoid is 143
Answer:


Δd = 
Explanation:
As
, when the car is making full stop,
.
. Therefore,

Apply the same formula above, with
and
, and the car is starting from 0 speed, we have

As
. After
, the car would have traveled a distance of

Hence 
As
we can simplify 
After t time, the train would have traveled a distance of 
Therefore, Δd would be 
Kinetic energy.
Kinetic energy is the type of energy observed in moving objects. In this case the football player is running, ie moving, so he/she must have kinetic energy.