Answer:
0.8s
Explanation:
Given parameters:
Height of shelf = 3m
Unknown:
Time it will take to hit the ground = ?
Solution:
To solve this problem, we use the expression below;
x = ut + 
gt²
x is the height
u is the initial velocity = 0m/s
g is the acceleration due to gravity = 9.8m/s²
t is the time taken = ?
Now insert the parameters and solve for t;
3 = (0 x t) +( x 9.8 x t²)
3 = 4.9t²
t² = 0.6
t = 0.8s
Answer:
- Particles smaller than atoms are called subatomic particles .
- There are three famous subatomic particles, proton, neutron and electron .
- The study of sub atomic particles are called particle physics
- These particles can be divided as Brayons and Leptons
- These particles are often held together by one of the four fundamental particles ( Weak force, strong force, electromagnetic force, gravitational force).
Answer:
Explanation:
The hippopotamus hearing threshold is 100dB
β = 100 dB
The threshold of human hearing is Io = 1 × 10^-12 W/m²
The sound intensity level is given as
β = 10•Log(I / Io)
100 = 10•Log(I / Io)
Divided Both sides by 10
100 / 10 = Log(I / Io)
10 = Log(I / Io)
Take inverse Logarithm ( antilog) of both sides
10^10 = 10^[Log(I / Io)]
10^10 = I / Io
Then,
I = 10^10 × Io
I = 10^10 × 1 × 10^-12
I = 1 × 10^-2 W/m²
I = 0.01 W/m²
The sound intensity is 0.01 W/m²
<span>The correct answer is C) a motor.
In particular, we are talking about an AC motor, which produces an alternating current. In an AC motor, a coil is immersed in a rotating magnetic field. Due to the motion of the magnetic field,the angle between the direction of the field and the surface enclosed by the coil changes. As a result, the magnetic flux through the coil changes over time (the magnetic flux is given by:
</span>
<span>
where B is the intensity of the magnetic field, A is the area enclosed by the coil and </span>
<span> is the angle between the direction of B and the perpendicular to the plane of the coil). For Faraday-Newmann-Lenz law, this change in flux induces an electromotive force (emf) into the coil, according to:
</span>
<span>
where the numerator is the variation of magnetic flux and dt is the time interval. This emf in the coil produced an electrical current in the circuit.</span>
<span>3) Neither precise or accurate.
This is because of the deviation between the measurements, they vary and are not within a good range. And they are not close to the accepted value. In order to be precise the measurements have to be relatively close to each other, and to be accurate they have to be close to the accepted value.</span>
