1. A car accelerating: When you press the gas pedal in a car, the engine exerts a force on the wheels. This force causes the car to speed up, meaning its velocity increases. The force is in the same direction as the car's motion, resulting in an increase in speed.
2. A ball thrown upwards: When you throw a ball upwards, your hand exerts a force on the ball, giving it an initial upward velocity. As the ball travels upwards, gravity exerts a downward force on it. This force slows the ball down until it momentarily stops at its highest point. The force of gravity acts in the opposite direction to the ball's motion, causing its velocity to decrease.
3. A hockey puck sliding to a stop: When a hockey puck is sliding across the ice, friction between the puck and the ice exerts a force on it. This force opposes the puck's motion, causing it to slow down and eventually come to a stop. The force of friction acts in the opposite direction to the puck's motion, resulting in a decrease in velocity.
