Figure 1
Figure 2
1. (7 points, suggested time 13 minutes)
A cart on a hori...
Feb 20, 2024
Figure 1
Figure 2
1. (7 points, suggested time 13 minutes)
A cart on a horizontal surface is attached to a spring. The other end of the spring is attached to a wall. The cart is initially held at rest, as shown in Figure 1. When the cart is released, the system consisting of the cart and spring oscillates between the positions x=+L and x=−L. Figure 2 shows the kinetic energy of the cart-spring system as a function of the system's potential energy. Frictional forces are negligible.
(a) On the graph of kinetic energy K versus potential energy U shown in Figure 2, the values for the x-intercept and y-intercept are the same. Briefly explain why this is true, using physics principles.
Figure 3
When the cart is at +L and momentarily at rest, a block is dropped onto the cart, as shown in Figure 3 . The block sticks to the cart, and the block-cart-spring system continues to oscillate between −L and +L. The masses of the cart and the block are m0 and 3m0, respectively.
(b) The frequency of oscillation before the block is dropped onto the cart is f1. The frequency of oscillation after the block is dropped onto the cart is f2. Calculate the numerical value of the ratio f1f2.
Solution by Steps
step 1
To solve the equation (f1f2)2=4m0m0, we first simplify the right side of the equation
step 2
Simplifying the fraction 4m0m0 gives us 41 because m0 cancels out in the numerator and denominator
step 3
Now we have (f1f2)2=41. To find f1f2, we take the square root of both sides
step 4
Taking the square root of both sides gives us f1f2=±21. However, since frequency cannot be negative, we discard the negative solution
Answer
f1f2=21
Key Concept
Solving a ratio of squares for the original ratio
Explanation
The ratio of the squares of two frequencies is equal to the ratio of their squares, and when taking the square root, we consider only the positive solution since frequency cannot be negative.