# Tutor profile: Bereket Z.

## Questions

### Subject: Geometry

I think of a shape with n sides whose interior angles sum up to 900 degrees, how many sides does my shape have?

I can always prove this relationship for you if you like, but I'd need to draw the shapes. Essentially the sum of all interior angles = (n-2)*180. 900/180= n-2 5=n-2 n=7

### Subject: Calculus

Explain the concept of instantaneous speed.

Let's say you're in a car with a pretty decent driver who steps on the gas just right so that the car cruises smoothly at one fixed speed. If I asked you to tell me what speed you were driving at any point in your cruise, your answer will be the same since your speed isn't changing. Now let's say you got in a car with a maniac who randomly smashes on the gas and all of a sudden your cars speed changes so sporadically, and I ask you to tell me what speed you were driving at, your answer would depend on what point in time of the drive you're referring to. So if you chose to give me your speed 10 minutes into the drive, you're basically going to chop up time into these really really small slices and focus on the slice that 10 minutes into your drive. in that slice you will measure how much of a distance your car traveled in that tiny time frame of your slice and calculate for speed (distance/time), and volla that is your instantaneous speed.

### Subject: Physics

You have a box of 5kg floating in space, and is initially stationary relative to you. But now you push on it for 3 seconds with a force of 10 N, what is it's new velocity?

When you apply a force to an object, it will accelerate; and all that means is its speed will change. If we use the expression F=ma, where F is force, m is mass and a is acceleration we can figure out what the acceleration of the 5kg box is. in this case, its acceleration is 2m s^(-2). this means every second the speed of the box increases by 2m's. since this force is applied for a total of 3 seconds, the total change in speed turns out to be 6 m/s. It's new velocity, therefore, is 6m/s.

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