Video Summary

**Newton's first law of motion states that an object at rest stays at rest and an object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.** This means that an object will not accelerate unless there is a net force acting on it. The net force is the sum of all the forces acting on an object. If the net force is zero, the object will not accelerate and will either stay at rest or continue moving at a constant velocity. **Examples:** * A ball sitting on the ground will not move unless it is kicked or thrown. * A car driving down the road will continue to move at a constant speed unless it hits the brakes or turns. * A rocket in space will continue to move in a straight line unless it is acted upon by gravity or some other force. **Applications:** Newton's first law of motion is used in many different applications, such as: * **Automobiles:** The design of automobiles is based on Newton's first law of motion. The wheels of a car provide a force that pushes the car forward, and the car will continue to move at a constant speed unless the brakes are applied or the car hits something. * **Rocketry:** Rockets are launched into space using Newton's first law of motion. The rocket engine provides a force that pushes the rocket upward, and the rocket will continue to move upward at a constant speed until it reaches space. * **Sports:** Newton's first law of motion is used in many different sports, such as baseball, football, and basketball. In baseball, the batter uses a bat to hit the ball, and the ball will continue to move in a straight line unless it is caught by a fielder or hits the ground. In football, the quarterback throws the ball to a receiver, and the receiver will continue to run with the ball unless he is tackled by a defender. In basketball, the player dribbles the ball, and the ball will continue to move in a straight line unless it is intercepted by a defender or hits the ground.