A 7.80 g bullet is initially moving at 660 m/s just before it penetrates a block of wood to a depth of 6.20 cm. (a) What is the magnitude of the average frictional force (in N) that is exerted on the bullet while it is moving through the block of wood? Use work and energy considerations to obtain your answer. N (b) Assuming the frictional force is constant, how much time (in s) elapses between the moment the bullet enters the block of wood and the moment it stops moving? S

Please don't use Chatgpt will upvote and give handwritten solution

Two blocks, A and B (with mass 45 kg and 120 kg, respectively), are connected by a string, as shown in the figure below. The pulley is frictionless and of negligible mass. The coefficient of kinetic friction between block A and the incline is μk = 0.26. Determine the change in the kinetic energy of block A as it moves from to ①, a distance of 15 m up the incline (and block B drops downward a distance of 15 m) if the system starts from rest. ] 37° A © B

A skateboarder with his board can be modeled as a particle of mass 80.0 kg, located at his center of mass. As shown in the figure below, the skateboarder starts from rest in a crouching position at one lip of a half-pipe (point). On his descent, the skateboarder moves without friction so that his center of mass moves through one quarter of a circle of radius 6.20 m. i (a) Find his speed at the bottom of the half-pipe (point Ⓡ). m/s (b) Immediately after passing point Ⓑ, he stands up and raises his arms, lifting his center of mass and essentially "pumping" energy into the system. Next, the skateboarder glides upward with his center of mass moving in a quarter circle of radius 5.71 m, reaching point D. As he passes through point ①, the speed of the skateboarder is 5.37 m/s. How much chemical potential energy in the body of the skateboarder was converted to mechanical energy when he stood up at point Ⓑ? ] (c) How high above point ① does he rise? m

A 31.0-kg child on a 3.00-m-long swing is released from rest when the ropes of the swing make an angle of 29.0° with the vertical. (a) Neglecting friction, find the child's speed at the lowest position. m/s (b) If the actual speed of the child at the lowest position is 2.40 m/s, what is the mechanical energy lost due to friction? ]

A force acting on a particle moving in the xy plane is given by F = (2yî + x²), where F is in newtons and x and y are in meters. The particle moves from the origin to a final position having coordinates x = 5.60 m and y = 5.60 m, as shown in the figure below. y (m) B (x, y) x (m) (a) Calculate the work done by F on the particle as it moves along the purple path (0 Ⓐ©). ] (b) Calculate the work done by ♬ on the particle as it moves along the red path (0 BC). J (c) Is F conservative or nonconservative? ○ conservative nonconservative

A 3.5-kg block is pushed 2.9 m up a vertical wall with constant speed by a constant force of magnitude F applied at an angle of 0 = 30° with the horizontal, as shown in the figure below. If the coefficient of kinetic friction between block and wall is 0.30, determine the following. (a) the work done by F J (b) the work done by the force of gravity ] (c) the work done by the normal force between block and wall J (d) By how much does the gravitational potential energy increase during the block's motion? ]

Physics different from a sea breeze from a land breeze

File Preview Design a capacitor for a special purpose. After graduating from medical school you and a friend take a three hour cruise to celebrate and end up stranded on an island. While looking for food, a spider falls on your friend giving them a heart attack. Recalling your physics, you realize you can build a make-shift defibrillator by constructing a capacitor from materials on the boat and charging it using the boat's battery. You know that the capacitor must hold 100 J of energy and be at 1000 V (fortunately this is an electric boat which has batteries that are 1000 V) to work. You decide to construct the capacitor by tightly sandwiching a single layer of Saran wrap between sheets of aluminum foil. You read the Saran wrap box and fortunately they tell you that it has a thickness 0.01 mm and dielectric constant of 2.3. The Saran wrap and foil are 40 cm wide and very long. How long is the final capacitor you build that saves your friend?