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Katarina [22]
3 years ago
5

Problem 1: a car is to be hoisted by elevator to the fourth floor of a parking garage, which is 52 ft above the ground. if the e

levator can accelerate at 0.7 ft/s2, decelerate at 0.35 ft/s2, and reach a maximum speed of 8 ft/s, determine the shortest time to make the lift, starting from rest and ending at rest.
Physics
1 answer:
djyliett [7]3 years ago
4 0
The working equation for this problem is written below:
x = v₀t + 0.5at², where x is the distance traveled, v₀ is the initial velocity, a is the acceleration and t is the time

Let's apply the concept of calculus. The maximum speed is equated to the derivative of x with respect to t.

dx/dt = 8 ft/s = v₀ + at

Since the it starts from rest, v₀ = 0

8 = at
t = 8/a  

The net acceleration is 0.7 - 0.35 = 0.35 ft/s². Thus,

t = 8/0.35 = 22.86 seconds
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Answer:

D)Not enough information

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According to Pascal's principle, the pressure exerted on the two pistons is equal:

p_A = p_B

Pressure is given by the ratio between force F and area A, so we can write

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Now we can rewrite the mass as the product of volume, V, times density, d:

\frac{V_A d_A g}{A_A}=\frac{V_B d_B g}{A_B}

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So we can further re-arrange the equation (and simplify g as well):

\frac{V_A d_A}{1}=\frac{V_B d_B}{2}

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We are also told that block B has bigger volume than block A: V_B > V_A. However, this information is not enough to allow us to say if the fraction on the right is greater than 1 or smaller than 1: therefore, we cannot conclude anything about the densities of the two objects.

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In a projectile, the horizontal acceleration is zero. The velocity remains constant at all times. However, the <u>vertical acceleration</u> is -9.81m/s^2.

Hope this helps!
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Answer:

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Answer:

e) indicated that the speed of light is the same in all inertial reference frames.

Explanation:

In 18th century, many scientists believed that the light just like air and water needs a medium to travel. They called this medium <em>aether</em>. They believed that even the space is not empty and filled with aether.

Michelson and Morley tried to prove the presence and speed of this aether through an interference experiment in 1887. They made an interferometer in which light was emitted at various angles with respect to the supposed aether. Both along the flow and against the flow to see the difference in the speed of light. But they did not find no major difference and thus it became the first proof to disprove the theory of aether.

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