Two crates, of mass 65 kg and 125 kg, are in contact and at rest on a horizontal

Question

Two crates, of mass 65 kg and 125 kg, are in contact and at rest on a horizontal surface (see figure). A 650 N force is exerted on the 65 kg crate. The coefficient of kinetic friction is0.08.

(a) Calculate the acceleration of the system.
_____________ m/s2 (to the right)

(b) Calculate the force that each crate exerts on the other.
_____________ N

(c) With the crates reversed, calculate the force that each crate exerts on the other .
_____________ N

Two crates, of mass 65 kg and 125 kg, are in contact and at rest on a horizontal surface (see figure). A 650 N force is exerted on the 65 kg crate. The coefficient of kinetic friction is0.08. (a) Calculate the acceleration of the system. _____________ m/s2 (to the right) (b) Calculate the force that each crate exerts on the other. _____________ N (c) With the crates reversed, calculate the force that each crate exerts on the other . _____________ N

Explanation / Answer

N1 = normal reaction between the block

N2 is normal reaction of 65 kg with ground

N3 = normal reaction of 125 kg with ground

balancing forces in horizontal direction for 65 kg

N1 - 650 - 0.08 x 65 x 9.8 = 0

N1 = 599.04 N

now friction force on 65 kg = 65 x 9.8x 0.08 = 50.96 N

friction force on 125 kg = 125 x 9.8x 0.08 = 98 N

motion will only occur when 125 kg mass moves thus the motion in such cases will be controlled by the heavier mass experiencing greater friction

equation of motion for 125 kg

N1 - .08 x 125 x 9.8 = 125 x a

a = 4 m/s^2

this will be the common acceleration

in case 125 is in front

650 - .08 x 9.8 x 125 = 552 N = normal reaction b/w the blocks

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

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