2 m/s or 2 m/s to the left. To The Questions. Question 1. Answer 1. Question 2. What is the impulse acting on the ball? (Down is positive)

Transcription

1 To The Questions Back to Briefcases Question 1 What is the final velocity of car A? (Pay attention to arrow direction!) Answer 1 2 m/s or 2 m/s to the left 50 points 25 points Question 2 What is the impulse acting on the ball? (Down is positive) 1

2 Answer N*s 50 points 75 points Question 3 Two balls are at rest at the top of a 45 o hill. Ball 1 has a mass of 2 kg. Ball 2 has a mass of 4 kg. The hill is 5 m high. When both balls reach the bottom of the hill, which one will have the greater momentum? Answer 3 Ball 2; both will have the same velocity, but ball 2 has a greater mass. 50 points 500 points Question 4 An 82 kg man drops from rest on a diving board 3.0 m above the surface of the water and comes to rest 0.55 s after reaching the water. What force does the water exert on him? (Down is positive) Answer N 50 points 10 points Question 5 A 0.40 kg soccer ball approaches a player horizontally with a velocity of 18 m/s to the north. The player strikes the ball and causes it to move in the opposite direction with a velocity of 22 m/s. What impulse was delivered by the ball to the player? (north is positive) 2

3 Answer 5 16 N*s 50 points 100 points Question 6 A 2250 kg car traveling to the west slows down uniformly from 20.0 m/s to 5.00 m/s. How long does it take the car to slow down if the force on the car is 8450 N to the east? Answer 6 4 seconds 50 points 300 points Question 7 A 2500 kg car traveling to the north is slowed down uniformly from an initial velocity of m/s by a 6250 N braking force acting opposite the car s motion. What is the car s velocity after 2.50 s? Answer m/s 50 points 150 points Question 8 An object's velocity is quadrupled but the mass is cut in half. What happens to its momentum? 3

4 Answer 8 doubled 50 points 20 points Question 9 A 200 g baseball is thrown toward home plate with a speed of 35 m/s. The batter hits the ball directly back at the pitcher with a speed of 45 m/s. Towards home plate is positive a) sketch a motion map to show the motion of the ball b) What is the change in momentum? Answer 9 50 points 5 points 16 kg m/s Question 10 A 2.5 kg ball is resting at the top of a 3 m high hill. If it rolls down to the bottom, what is the ball's momentum at the bottom? (Assume the hill is frictionless) Question 11 Answer kg m/s Below is a graph depicting the force acting on a 45 kg sled over a period of time 50 points 1000 points What is the impulse acting on the sled from 30 seconds to 90 seconds? 4

5 Answer 11 Question 12 Below is a graph depicting the force acting on a 45 kg sled over a period of time 540 N*s 50 points 10 points If the sled was moving +27 m/s at 90 s, how fast will it be moving at 150 s? Answer 12 7 m/s 50 points 1 point Question 13 A 1500 kg car traveling at m/s to the south collides with a 4500 kg truck that is initially at rest at a stoplight. The car and truck stick together and move together after the collision. What is the final velocity of the two vehicle mass? Answer m/s Question 14 A.0005 kg bug hits a 4500 kg truck. Which one experiences the greater impulse? 50 points 15 points 5

6 Answer 14 Same 50 points 400 points Question 15 Two roller skaters are facing each other and push off one another. The first roller skater rolls away at 5 m/s and the second rolls away at 7 m/s. If the first roller skater has a mass of 85 kg, what is the mass of the second roller skater? Answer kg 50 points 30 points Question 16 A grocery shopper tosses a 9.0 kg bag of rice into a stationary 18.0 kg grocery cart. The bag hits the cart with a horizontal speed of +5.5 m/s toward the front of the cart. What is the final speed of the cart and bag? Answer m/s 50 points 250 points Question 17 A 16.0 kg canoe moving to the left at 12 m/s makes and elastic head on collision with a 4.0 kg raft moving to the right at 6.0 m/s. After the collision, the raft moves to the left at 22.7 m/s. Disregard any effects of the water. Find the velocity of the canoe after the collision. Left is positive. 6

7 Answer m/s 50 points 5 points Question 18 Two astronauts each with a mass of 75 kg are headed toward each other. The first astronaut has a velocity of +2.5 m/s while the other has a velocity of 1.5 m/s. In an attempt to stop each other, they collide and move together. What is their final velocity? Answer m/s 50 points 35 points Question 19 A 5.0 kg object moving to the right at 2.0m/s makes a perfectly elastic head on collision with a 2.0 kg object moving in the opposite direction at 5.0m/s. Find the velocity of each object after the collision. Right is positive Answer 19 Object 1: 2.0 m/s Object 2: +5.0 m/s Question 20 A 3.0kg ball traveling at +15m/s strikes a 2.0kg ball which is initially at rest. After, the 3.0 kg ball is traveling at +10 m/s. What is the velocity of the second ball? 50 points 125 points 7

8 Answer m/s 50 points 70 points 8