Answer:
the answers, the correct one is A v= 22.5 m/s
Explanation:
We can solve this problem using the concepts of conservation of mechanical energy
Starting point. Lowest point of the trajectory
Em₀ = K = ½ m v₀²
Final point. When it is at a height of y = 20 m
= K + U = ½ m v² + mg y
how energy is conserved
Emo = Emf
½ m v₀² = ½ m v² + m g y
v² = v₀² + 2 g y
let's calculate
v²2 = 30 2 + 2 9.8 20
v² = 508
v²= ra 508
v² = 22.54 m / s
When checking the answers, the correct one is A
Answer:
1. s
2. m
3. start m/s
4. end m/s
5. m/s^2
Explanation:
1. t is the suffix for the time and it is related to seconds [s]
2. d is the suffix for distance and it is related to meters [m]
3. Vi is the suffix for the initial velocity and it is related to meters per second [m/s]
4. Vf is the suffix for the final velocity and it is related to meters per second [m/s]
5. a is the suffix for the acceleration and it is related to meters per squared second [m/s^2]
The answer is the the first one
<span>To
determine the energy stored in the magnetic field, use the formula: E = ½ LI2
where E is the energy stored, L is the inductance (units: Henry), and I is the
current (units: Ampere). </span>
<span>Correspondingly, L = (µN2A)/l,
where, µ = permeability of medium (in this case, air), N = no. of turns, A = cross-sectional
area, and l = length. Given: N = 68 turns, l = 8 cm, d = 1.2 cm, and I = 0.77
A, other necessary variables are A = 1.13 cm2 and µair =
1.2566 x 10-6 H/m. Applying the formula and checking that the units
agree with each other, the final answer is 2.4352 x 10-6 J.</span>
The mass of the (elevator + person) is (2,000 kg + 60 kg) = 2,060 kg .
The weight is (mass x gravity) = (2,060 x 10) = 20,600 newtons
Work = (force x distance) = (20,600 newtons x 24m) = <em>494,400 joules</em>
The speed, acceleration, and how much time it takes don't make any
difference, unless you want the average power during the lift.
Power = (work)/(time) =
494,000 J / (24/4 m) =
494,000 J / 6 sec = <em><u>82,400 watts</u></em> wow !