Physics Final Questions & Answers

Physics Final Questions & Answers A 20 kg shopping cart moving at a velocity of 0.5 m/s collides with a store wall and stops. The momentum of the shopping cart - CORRECT ANSWER- decreases. A 75 kg person walking around a corner bumped into an 80 kg person who was running around the same corner. The momentum of the 80 kg person - CORRECT ANSWER- decreased. A ball is dropped from a person's hand to Earth. Identify an action-reaction pair in this situation. - CORRECT ANSWER- Earth exerts a force on the ball; the ball exerts a force on the Earth. A ball is thrown up into the air. At what point in its trajectory will its acceleration equal zero? - CORRECT ANSWER- Never A ball is whirled on a string, then the string breaks. What causes the ball to move off in a straight line? - CORRECT ANSWER- Inertia A ball with a momentum of 4.0 kg * m/s hits a wall and bounces straight back without losing any kinetic energy. What is the change in the ball's momentum? - CORRECT ANSWER- -8.0 kg * m/s A baseball catcher throws a ball vertically upward and catches it in the same spot as it returns to the mitt. At what point in the ball's path does it experience zero velocity and nonzero at the same time? - CORRECT ANSWER- At the top of its path. A billiard ball collides with a second identical ball in an elastic head-on collision. What is the kinetic energy of the system after the collision compared with the kinetic energy before the collision? - CORRECT ANSWER- unchanged A billiard ball collides with a stationary identical billiard ball in an elastic head-on collision. After the collision, which of the following is true of the first ball? - CORRECT ANSWER- It comes to rest. A block of wood supported by two concrete blocks is chopped in half by a karate instructor. Identify an action-reaction pair, and compare the forces exerted by each object. - CORRECT ANSWER- Guy exerts chopping force on the wood, wood exerts a chopping force on the karate instructor. A bug moves 10 cm north, 2 cm south, then 5 cm north, what is its displacement? - CORRECT ANSWER- 13 cm north A car goes forward along a level road