The drawing shows a large cube (mass = 21.0 kg) being accelerated across a horiz

Question

The drawing shows a large cube (mass = 21.0 kg) being accelerated across a horizontal frictionless surface by a horizontal force P. A small cube (mass = 3.6 kg) is in contact with the front surface of the large cube and will slide downward unless P is sufficiently large. The coefficient of static friction between the cubes is 0.710. What is the smallest magnitude that P can have in order to keep the small cube from sliding downward?

The drawing shows a large cube (mass = 21.0 kg) being accelerated across a horizontal frictionless surface by a horizontal force P. A small cube (mass = 3.6 kg) is in contact with the front surface of the large cube and will slide downward unless P is sufficiently large. The coefficient of static friction between the cubes is 0.710. What is the smallest magnitude that P can have in order to keep the small cube from sliding downward?

Explanation / Answer

If the small cube does not slide down, the friction force between the cubes must be mg=36N,

so the normal force by the large cube to small cube (in forward direction) must be f/u

32/0.71=45N.

This will provide the small cube an acceleration of F/m

=45/3.6

=12.5m/s^2.

The large cube must have the same acceleration forward with the small cube, so the force P that provide both cubes with the acceleration is P=(M+m)a

=(21+3.6)*12.5

=307.5N

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

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