Falling Objeets and Drag- Pre-Lab In this lab we will see what the motion of dif

Question

Falling Objeets and Drag- Pre-Lab In this lab we will see what the motion of different (in shape or mass) falling objects looks like and how it s affected by air resistance. In the case where the air resistance (drag) is not negligible, the falling object is experiencing two forces, weight and drag. While the weight remains the same throughout the motion, the drag does not. The value of the drag force (D) depends on the square of the velocity of the falling object. Below, the figure shows the directions of the two forces acting on the body while it is falling. Drag, D v2 Weight. W = mg Problem: To better understand the concept of non-constant force, in this case drag, think of when you are driving your car and put your hand outside of the window (don't do it though, it might be risky). When do you experience more drag, when you are driving at 20 mph or 70 mph? Based on the information given above about the drag, explain your answer. How does the drag force acting on your hand change when accelerating from 20 mph to 70 mph?

Explanation / Answer

Since drag force is directly proportion to square of the velocity, lets asume that

Drage Force = K*v^2, where K is a constant. In this equation, thedrag force is directly proportional to the square of the velocity.

So when we go at 20 mph, the drag force is lesser as compared to when we go at 70 mph as drag force increases with increase in speed.

Let R20 be the drag force when driving at 20 mph and R70 be the frag force when driving at 70 mph.

so, R20 = K*(20)^2 and R70 = K*(70)^2

so,

R70/R20 = (70)^2/(20)^2

=24.5

so drag force increases by a factor of 24.5 when the speed increases from 20 mph to 70 mph.

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