Answer:
The found acceleration in terms of h and t is:

Explanation:
(The complete question is given in the attached picture. We need to find the acceleration in terms of h and t in this question)
We are given 3 stages of movement of elevator. We'll first model them each of the stage one by one to find the height covered in each stage. After that we'll find the total height covered by adding heights covered in each stage, and equate it to Total height h. From that we can find the formula for acceleration.
<h3>
</h3><h3>
Stage 1</h3>
Constant acceleration, starts from rest.
Distance = 
Velocity = 
<h3>Stage 2</h3>
Constant velocity where
Velocity = 
Distance =
<h3>

</h3><h3 /><h3>Stage 3</h3>
Constant deceleration where
Velocity = 
Distance =

<h3>Total Height</h3>
Total height = y₁ + y₂ + y₃
Total height = 
<h3 /><h3>Acceleration</h3>
Find acceleration by rearranging the found equation of total height.
Total Height = h
h = 5a(t₁)²

Answer:
<em>The direction of the magnetic field on point P, equidistant from both wires, and having equal magnitude of current flowing through them will be pointed perpendicularly away from the direction of the wires.</em>
Explanation:
Using the right hand grip, the direction of the magnet field on the wire M is counterclockwise, and the direction of the magnetic field on wire N is clockwise. Using this ideas, we can see that the magnetic flux of both field due to the currents of the same magnitude through both wires, acting on a particle P equidistant from both wires will act in a direction perpendicularly away from both wires.
Answer:
μ = 0.18
Explanation:
Let's use Newton's second Law, the coordinate system is horizontal and vertical
Before starting to move the box
Y axis
N-W = 0
N = W = mg
X axis
F -fr = 0
F = fr
The friction force has the formula
fr = μ N
fr = μ m g
At the limit point just before starting the movement
F = μ m g
μ = F / m g
calculate
μ = 34.8 / (19.8 9.8)
μ = 0.18
Answer:
B
Explanation:
Acceleration = rate of change in velocity
a = (21-12)/(0.45) = 20cm/s^2