I only need 4- B,C,D and 5- D,E and all parts for 6

AP Physics 1 U4 - WS3 - Friction Unit 4 - Forces & Acceleration page 1 11/13/2018 1. A block weighing w is moved at constant speed v over a horizontal surface by a force F applied parallel to the surface. Derive an expression for the coefficient of kinetic friction in terms of the relevant variables and constants. b. Derive an expression for the acceleration of the block if fx = 0. 2. A force F is applied in a horizontal direction to a 50 kg crate that is at rest on a level floor. The coefficient of kinetic friction is 0.3. The coefficient of static friction is 0.7. a. If F is 200 N, what is the force of friction on the crate and what is its acceleration? . If F is 300 N, what is the force of friction on the crate and what is its acceleration? C. If F is 400 N, what is the force of friction on the crate and what is its acceleration? d. If F is 350 N, what is the force of friction on the crate and what is its acceleration? e. If F is 350 N and the crate is already moving, what is the force of friction on the crate and what is its acceleration? 3. A block of mass m is allowed to slide down a ramp angled at 0 with a coefficient of kinetic friction of Mx. Answer in terms of the given variables (m, 0, g, and uk). a. Derive an expression for the frictional force. m b. Derive an expression for the acceleration of the block. c. Derive an expression for the angle that will allow the block slide down the incline with a constant velocity. 4. An applied force F pulls on a block with mass m resting on a horizontal surface. The force is directed upwards at an angle of 20, and the coefficient of kinetic friction is 0.15. The coefficient of static friction is 0.25. a. Derive an expression for the normal force. b. Derive an expression for the friction force. c. Derive an expression for the acceleration of the block. d. What would the coefficient of kinetic friction have to be for the block to move at constant speed? 5. A box of bananas weighing 40.0 N rests on a horizontal surface. The coefficient of static friction between the box and the surface is 0.40, and the coefficient of kinetic friction is 0.20. . If no horizontal force is applied to the box and the box is at rest, how large is the friction force exerted on the box? b. What is the magnitude of the friction force if a monkey applies a horizontal force of 6.0 N to the box and the box is initially at rest? C. What minimum horizontal force must the monkey apply to get the box moving? d. What minimum horizontal force must the monkey apply to keep the box moving at a constant velocity (once it is moving)? . If the monkey applies a horizontal force of 18.0 N, what is the magnitude of the friction force and what is the box's acceleration? 6. Two lovers are parked 20.0 m from the edge of a cliff in a car whose mass, including that of the occupants is 1000 kg. A jealous suitor ties a rope to the car's bumper and a 200 kg rock to the other end of the rope. He then lowers the rock over the edge of the cliff, and the car, which is in neutral (negligible friction), accelerates toward the edge. a. What is the acceleration of the car towards the edge? Two seconds after the car begins to accelerate, one of the lovers realizes what is happening and applies the parking brake of the car, increasing the coefficient of kinetic friction between the wheels and ground to 0.25. b. Where does the car stop? The jealous suitor, seeing the situation, grabs on to the hanging rope, adding his 70 kg to the 200 kg rock. The car still remains motionless. What is the minimum coefficient of static friction between the car wheels and the ground? Having been frightened, the two lovers get out of the car, reducing the mass of the car by 180 kg. d. Assuming that the answer to c above is the coefficient of static friction between the car wheels and the ground, how long does the jealous suitor look up the rope until he sees the car above him sticking out over the cliff edge? If the cliff is 50 m tall, how long does it take the car to hit the bottom of the cliff? e. f. With what vertical velocity does the car hit the ground (and perhaps the jealous suitor)