a 40kg crate is at rest on a level surface. If the coefficient of static friction between the crate and the?

Question

surface is 0.69, what horizontal force is required to get the crate moving?

Answer 1

according to newton's second law. Unbalanced forces cause acceleration.

To get the box moving, the horizontal force must be at least equal static friction force.

Friction = μ (normal force)

because the crate rest on a level surface, the normal force is equal to the weight of the crate

Friction = μ (weight)

weight = mass * acceleration due to the earth

acceleration due to the earth is 9.8 m/s^2

Friction = .69 (40 * 9.8)
Friction = 270.48N

Again, to move the box, the horizontal force must be at least equal to static friction. We know that static friction is 270.48N, then the minimum horizontal force must be also 270.48N

Answer 2

the reaction force must be overcome so a horizontal force the is just greater than
40*g*0.69, will get it moving

j