Figure 1 A Three blocks, labeled A, B, and C, are connected by essentially massless strings that run over essentially massless and frictionless pulleys (as shown in Figure A above). Block A hangs straight down. The string from block A connects to block B which is sliding up and to the left along an inclined plane. The plane is inclined at an angle of theta = 0 = 52 degrees away from vertical. The coefficient of kinetic friction between block B and the plane is 0.38. Block B is connected by a different string to block C which | straight down. Block A has a mass of 4.1 kg. Block B has a mass of 3.7 kg. Block C has a mass of 2.5 kg. Block A is moving down and block C is moving up (the strings do not stretch). The only significant forces acting on the blocks are friction acting on block B, normal forces, tension forces, and gravity (with g = 9.81 m/s?). Calculate the acceleration (in units of meters per second squared) of block A. For block A, a downward acceleration is considered positive, and the sign of your answer is important.

A 65 kg person running at 2.0 m/s jumps onto the skim board at right. The skim board is 50 cm wide and 120 cm long, with an area of 0.60 m². Part A Draw a sketch of this situation. Part B If the person jumps onto the board on sand with a coefficient of friction of f=0.50, what force will resist the forward movement of the board [N]? Recall the friction force is the normal force times the coefficient of friction. Part C Now assume the person jumps onto the board on a 0.50 cm film of fresh water at 30°C. Use Newton's law of viscosity to estimate the force resisting the forward movement of the board.

Two blocks are connected by a massless rope. The rope passes over an ideal (frictionless and massless) pulley such that one block with mass m1 = 12.25 kg is on a horizontal table and the other block with mass m2 = 7.5 kg hangs vertically. Both blocks experience gravity and the tension force, T. Use the coordinate system specified in the diagram. a.)  Assuming friction forces are negligible, write an expression, using only the variables provided, for the acceleration that the block of mass m1 experiences in the x-direction. Your answer should involve the tension, T. b.)  Under the same assumptions, write an expression for the acceleration, a2, the block of mass m2 experiences in the y-direction. Your answer should be in terms of the tension, T and m2. c.) Carefully consider how the accelerations a1 and a2 are related. Solve for the magnitude of the acceleration, a1, of the block of mass m1, in meters per square second. d.)Find the magnitude of the tension in the rope, T, in newtons.

You're driving home from the grocery store at 12 m/s with a 7.0 kg bag of groceries on the front seat when the light ahead turns red. Part A What is the shortest distance in which you can stop, after the brakes are applied, without the groceries sliding off the seat? The static and kinetic coefficients of friction are, respectively, 0.65 and 0.45. Assume that the surface of the seat is horizontal. Express your answer with the appropriate units. ► View Available Hint(s) Ax= HÅ Value Units ?

A sledge loaded with bricks has a total mass of 18.7 kg and is pulled at constant speed by a rope inclined at 19.5° above the horizontal. The sledge moves a distance of 19.4 m on a horizontal surface. The coefficient of kinetic friction between the sledge and surface is 0.500. Find parts a-c.

THIS QUESTION IS NOT GRADED.

A 1,040-N crate is being pushed across a level floor at a constant speed by a force  F  of 390 N at an angle of 20.0° below the horizontal, as shown in the figure a below. Two figures show a side view of a crate positioned upon a horizontal surface. Figure (a): An arrow pointing downward and to the right is labeled vector F and forms an angle of 20° below the horizontal as it approaches the upper left edge of the crate. Figure (b): An arrow pointing upward and to the right is labeled vector F and forms an angle of 20° above the horizontal as it extends from the upper right edge of the crate. (a) What is the coefficient of kinetic friction between the crate and the floor? (Enter your answer to at least three decimal places.)(b) If the 390-N force is instead pulling the block at an angle of 20.0° above the horizontal, as shown in the figure b, what will be the acceleration of the crate? Assume that the coefficient of friction is the same as that found in part (a).

An 8.00 kg crate sits on an inclined plane that is inclined at 33.0 above the horizontal. The coefficient of kinetic friction between the crate and the surface of the plane is 0.300. A constant horizontal force F = 28.0 N is applied to the crate (Figure 1), and the crate moves down the plane. Part A If the crate is initially at rest, find its speed 2.00s after the force is applied? Express your answer with the appropriate units. HA Value Units Figure 1 of 1> Submit Request Answer Provide Feedback F 33.0°

B In the figure, block A has a mass of 9.06 kg. It rests on a smooth (assume frictionless) horizontal table and is connected by a very light horizontal string over an ideal pulley to block B, which has a mass of 2.80 kg. When block B is gently released from rest, how long does it take block B to travel 76.7 cm? Report your answer in seconds.

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