A block of mass M1 = 3 kg rests on top of another block of mass M2 = 5 kg. As shown in the figure, the top block is connected by a cord to a wall at left. The bottom block rests on a frictionless inclined plane of angle theta = 20o and has a force F applied to it down the plane. If the minimum force for which the bottom block will begin to slide has magnitude F = 2.5 N, what is the coefficient of static friction (us) between the two blocks?

You are pushing a rubber crate against a concrete floor. The two surfaces have a static coefficient of friction of 0.61 and a kinetic coefficient of friction of 0.49. The floor is horizontal, and the crate has a mass of 25.0 kg, and is initially at rest. You are pushing with a horizontal force of 100 N. What is the magnitude of the force of friction in this case? Give your answer in units of N, to three significant figures.

A block of mass m1 = 3.9 kg is placed on top of a block with mass m2 = 5.4 kg. A force, F = is applied to m2, at an angle 16.1 degrees above the horizontal.  If the coefficient of static friction between all moving surfaces is 0.42 and the coefficient of kinetic friction is 0.32, determine the magnitude of the minimum force that will get the blocks moving.

A heavy sled is being pulled by two people, as shown in the figure. The coefficient of static friction between the sled and the ground is , = 0.579, and the kinetic friction coefficient is = 0.419. The combined mass of the sled and its load is m = 351 kg. The ropes are separated by an angle = 21.0. and they make an angle 0 = 30.1° with the horizontal, Assuming both ropes pull equally hard, what is the minimum rope tension required to get the sled moving? 1214.39 minimum rope tension: incorrect If this rope tension is maintained after the sled starts moving, what is the sled's acceleration? 1.56 acceleration: Attempt 1 N m/s?

Force T pulls at angle a up from the horizontal on a section of pipe of weight W as shown, but the pipe remains motionless. The coefficient of static friction between pipe and floor is µ. We know that the magnitude of the total frictional force on the pipe by the floor is: 1(c T. A) 27 cos a B) µ(W +T sin a) C) µW +T cos a D) T cosa W A B

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A block is placed on a wooden plank, which is initially horizontal.  One end of the plank is slowly raised to make it more and more inclined, and for a while the block stays in place on the plank and doesn't slide due to static friction.  Finally, when the plank reaches an incline of 56.3oabove horizontal, the block begins to slide.  What is the  coefficient of static friction between the block and the plank?

The diagram shows a block of mass m = 3.50 kg resting on a plane inclined at an angle of 0 = 40° to the horizontal. The coefficient of static friction between the block and the plane is μstatic = 0.30, and the block is stationary but just on the point of sliding down the slope. Ff F₁ 3 mg N 0 The diagram shows the four forces acting on the block: an applied force F₁ acting perpendicular to the slope (in the -y direction), the block's weight mg, the normal reaction force N and the force of static friction, Ff. In this case, the force of static friction acts up the slope, opposing the tendency of the block to move down the slope. Find the the minimum magnitude of the applied force F₁ that can be exerted if the block is to remain stationary. Specify your answer by entering a number into the empty box below.

A block with a mass of 9.32 kg is placed on a ramp. The ramp has an incline of ? = 20.2 degrees from the horizontal. The static coefficient of friction between the block and ramp is μs = 0.255, and the kinetic coefficient of friction between the block and ramp is μk = 0.134. A force, F, is exerted on the block as shown. Note that the force F is parallel with the ramp. What is the smallest value (magnitude) for the force, F, in Newtons that can be exerted on the block to hold the block stationary on the ramp?  What is the largest value (magnitude) for the force, F, in Newtons that can be exerted on the block while still holding the block stationary on the ramp?  What value (magnitude) for the force, F, is needed to move the block up the ramp at a constant speed?

You are pushing a wooden crate against a rubber floor. The two surfaces have a static coefficient of friction of 0.45 and a kinetic coefficient of friction of 0.38. The floor is horizontal, and the crate has a mass of 25.0 kg, and is initially at rest. You are pushing with a horizontal force of 155 N. What is the magnitude of the force of friction in this case? Give your answer in units of N, to three significant figures.