Sketch situation, use coordinate system and assign direction with + and - signs

Problem 1 Consider a hockey puck on an ice rink. At one point, the puck is hit giving it an initial velocity moving towards a net one the other side of the rink. The moving puck decelerates (due to friction) until it finally stops just beneath the mouth of the net. The puck initially moves at 25 km/hr and is in motion for 55 s.

• What is the deceleration of the puck?
• How far does the puck travel?
• What is the puck's velocity when it has traveled half the total distance?
• How much time has elapsed for the puck to travel half the distance?

Problem 2 Consider a ball falling off the top of a building. The ball falls for 5 s and then hits the ground. The ball starts from rest. Acceleration (a) is 9.8 m/s².

• How tall is the building from which the ball fell?
• What is the ball's velocity just before it hits the ground?