The block in Figure 7-11a lies on a horizontal frictionless surface and is attac

Question

The block in Figure 7-11a lies on a horizontal frictionless surface and is attached to the free end of the spring, with a spring constant of 65 N/m. Initially, the spring is at its relaxed length and the block is stationary at position x = 0. Then an applied force with a constant magnitude of 3.3 N pulls the block in the positive direction of the x axis, stretching the spring until the block stops. Assume that the stopping point is reached. What is the position of the block? m What is the work that has been done on the block by the applied force? j What is the work that has been done on the block by the spring force? J During the block's displacement, find the following values. The block's position when its kinetic energy is maximum. m The value of that maximum kinetic energy. mJ

Explanation / Answer

(a) block will stop when work done by spring is equal to work done by applied force, so

(1/2) * 65 * x^2 = 3.3 * x

x = 0.10154 m

(b) work done by appl force = force * x = 3.3 * 0.10154 = 0.3351 Joules

(c) spring does the same work but negative -0.3351 Joules

(d) KE is max when force of spring equals applied force

65 * x = 3.3 x = 0.05077 m

(e) work done by spring = -(1/2) * 65 * 0.05077^2 = -0.08377 Joules

work done by appl force = 3.3 * 0.05077 = 0.16754 Joules

KE = total work = 0.16454 - 0.08377 = 0.08377 J = 83.77 mJ

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.