# Tutor profile: Emma P.

## Questions

### Subject: Product Design

In the project outline for a required design, what is the difference between a project requirement vs. a specification? Also provide an example of the two.

A requirement is a need or function the product must meet or should perform. A specification is a technical standard a product must satisfy and may require analysis or testing. An example would be if you were tasked with designing a shoe. A requirement would be that the sole of the shoe must be made with rubber. A specification would be that the shoe must be able to withstand 5,000 steps before failure for a person 100-200 lbs.

### Subject: Mechanical Engineering

For a cantilever beam with a single point load at the free end, where does maximum bending stress and maximum deflection occur?

The bending stress is zero at the beam's neutral axis, which is the centroid of the beam's cross section. The bending stress increases linearly away from the neutral axis. The maximum bending stress occurs a the top and bottom of the beam. For a downward point load the top will be in tension and the bottom will be in compression. In cantilever beams, the maximum deflection occurs at free end

### Subject: Calculus

The following function gives the particle's position at ant time t ≥ 0 [s], x(t) = -t^3+3t^2-4 [m] . What is the velocity of the particle when its acceleration is zero.

First, the velocity function of the particle is the derivative of its position function. So v(t)= x'(t). Therefore v(t) = -3t^2+6t. The acceleration of the particle is the derivative of its velocity function so a(t)=v'(t)=x''(t). Therefore a(t)= -6t+6. We then set a(t)=0 and solve for the time when the acceleration is 0. So a(t)=0= -6t+6. This gives us t=1. We now know that the accerlation is zero when t-1, so therefore we solve for the velocity at this time, so v(1)= -3(1)^2+6*1 which gives us v(1)=3. So the final answer is that the velocity of the particle when its acceleration is zero is 3 [m/s].

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