PY 205 C5 H3:

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A car moves along the path shown in the diagram. The position of the car at different instants in time is represented by the dots on the diagram; the car starts at point 1 and moves to point 5. _ l1 - 1' zip ( ' 1) rip (1) [n the questions below, zii is rate of change of the car's momentum, m ii is the component of at that is parallel to the car's momentum, and 'l' t is the component perpendicular to the car's momentum. All; ./l\\. new "Banilude Select the letter corresponding to the arrow (a-j) that best indicates the direction of the following vector quantities at each point. At point 2, the car's speed is increasing. What is the direction of the car's momentum at point 2? ii, 1 What is the direction of the (\"all at point 2? M5 What is the direction of the (rill at point 2? At point 3, the car's speed is not changing. What is the direction of the car's momentum at point 3? i? What is the direction of the (M ii at point 3? ii)? What is the direction of the (W); at point 3? At point 4, the car's speed is increasing. What is the direction of the car's momentum at point 4? my what is the direction of the (m ii at point 4? .i,: What is the direction of the (W). at point 4? At point 5, the car's speed is decreasing. What is the direction of the car's momentum at point 5? Select ll); What is the direction of the ('Oii at point 5? ll)? What is the direction of the (rill at point 5? \fA child of mass 23 kg swings at the end or an elastic cord. At the bottom of the swlng, the child's veloclty is horizontal, and the speed is 7 m/s. At this instant the cord is 4.50 m long. (Take the +x direction to be horizontal and to the right, the +y direction to be upward, and the +1 direction to be out of the page.) (a) At this instant, what is the parallel component of the rate of change of the child's momentum? d E _ dt (kg m/s)/s (b) At this instant, what is the perpendicular component of the rate of change of the chlld's momentum? ' .2 e k . IDI dt ( 9 m/5)/s (c) At this instant, what is the net force acting on the child? Fnet : N (d) what is the magnitude of the force that the elastic cord exerts on the child? (It helps to draw a diagram of the forces.) que to coral : N (e) The relaxed length of the elastic cord is 4,43 m. What 'ls the stiffness or the cord? (Use the exact value you entered in part (d) to make this calculation) ks : N/m A Ferris wheel is a vertical, circular amusement ride With radius 9 m. Riders sit on seats that swivel to remain horizontal. The Ferris wheel rowtes at a constant rate, going around once in a 5. Consider a rider whose mass is 56 kg. At the bottom of the ride, what is the pardllel component of the iate of change of the rider's momentum? glib : . at p kg m/s/s At the bottom of the ride, what is the perpendicular component or the rate of change of the rider's momentum? \".2 _ . lpl dt kg m/s/s At the bottom of the ride, what is the vector gravitational force exerted by the Earth on the rider? Pg,\" : N At the bottom of the ride, what is the Vector force exerted by the Seat on the rider? Pby seat = N Next consider the situation at the top of the ride. At the top of the ride, what is the parallel component of the rate of change of the rider's momentum7 ELEL , dt k9 rills/s At the top or the ride, what is the perpendicular component or the iate of change of the rider's momentum? i e . lldt e kg m/s/s At the top or the ride, what is the vector gravitational force exerted by the Earth on the rider? P9,\" = N At the top of the ride, what is the vector force exerted by the seat on the rider? Fby seat : N A rider feels heavler it the electric, interatoinic contact force of the seat on the rider is larger than the rider's weight mg (and the rider sinks more deeply into the seat cushion). A rider feels lighter if the contact force or the seat is smaller than the rider's weight (and the rider does not sink as far into the seat cushion). Does a rider feel heavier or lighter at the bottom of a Ferris wheei ride? lighter heavier Does a rider feel heaVIer or lighter at the top of a Ferris wheel ride? heavier lighter In the dark in outer space, you observe a glowing ball of known mass 4 kg moving in the xy plane at constant speed in a circle of radius 7 m, with the center of the circle at the origin ( m). You can't see what's making it move in a circle. At time t = 0 the ball is at location m and has velocity m/s. (a) On your own paper draw a diagram of the situation, showing the circle, and showing the position and velocity of the ball at time t = 0. The diagram will help you analyze the situation. Use letters a-j to answer questions about directions (+x to the right, +y up): - j zero magnitude (b) At time t = 0, what is the direction of the vector p? ( ---Select--- 4) (c) At time t = 0, what are the magnitude and direction of p, the parallel component of P? magnitude = kg . m/s/s ---Select--- 4 (d) At time t = 0, what are the magnitude and direction of Ip|-, the perpendicular component of UP? magnitude = kg . m/s/s ---Select--- 4 (e) At time t = 0, even though you can't see what's causing the motion, what can you conclude must be the direction of the vector Fnet? (---Select--- !) (f) At time t = 0, even though you can't see what's causing the motion, what can you conclude must be the vector Fnet? Fnet = (g) You learn that at time t = 0, two forces act on the ball, and that at this instant one of these forces is F1 = N. What is the other force? F2 =In outer space a rock of mass 3 kg is attached to a long spring and swung at constant speed in a circle of radius 6 m. The spring exerts a force of constant magnitude 680 N. What is the speed of the rock? |7| : m/s The direction of the spring force is in the direction of motion (tangential to the circle). away from the center of the circle (radially outward). toward the center of the circle (radially inward). opposite the direction of motion (tangential to the circle). The relaxed length of the spring is 5.6 m. What is the stiffness of this spring? .k5 = N/m