Grade 5 | SCIENCE | Unit 4 - Concept 1 - Lesson 2 | Forces

شرح ساينس الصف الخامس الابتدائي لغات مستر احمد الباشا ساينس خامسة ابتدائي لينك تحميل الملزمة https://drive.google.com/file/d/13h4b... لينك تليجرام https://t.me/mrahmedelbashagroup In this part : 1. Force It is a pull or a push that is applied to an object. Forces can affect different objects in two ways which are contact force and noncontact force, where: In contact force, the two objects need to contact each other for the motion of one object, as when you kick a ball, your foot must contact the ball to make it move. In noncontact force, the two objects do not need to touch or contact each other for the motion of one object, as the magnet does not need to touch the paper clips to attract them. How things move • Forces can pull or push objects in different directions. • Some forces are weak, like the push force needed to move a toy car, while other forces are strong, like the push force needed to move a real car. Types of forces 1 The following examples show the cause and the effect of some different types of forces. Examples: Magnet has a kind of invisible force that cannot be seen, known as magnetism. 1. Magnetism It is the force of attraction or repulsion between two magnets or between a magnet and an object. Magnet can exert a pulling force or a pushing force using the force of magnetism as follows: • Pulling force of magnet: Cause: A magnet pulls paper clips up. Effect: Paper clips move to the magnet. • Pushing force of magnet: Cause: A magnet pushes away another magnet. Effect: The other magnet is pushed away. 2 Cause: Wind pushes on the blades of a wind turbine. Effect: Wind turbine blades move. 3 Cause: You squeeze a spring. Effect: The spring pushes back when you leave it free. 4 Cause: Gravity pulls a cup you drop to the floor. Effect: The cup falls to the ground. What Is Gravity ? • We know gravity is a force because we can see its effects around us, such as when something falls. For example: -An egg could slip out of your hand and fall to the floor. When you drop a ball or a book, it falls down toward the ground. The force of gravity keeps us from floating into space like that happens with astronauts. • In space, there are big and small planets, where bigger planets have more gravity than that of smaller planets. • The force of gravity keeps the planets revolve in their orbits or on fixed paths around the Sun. The Force of Gravity What goes up, must come down? Gravity changes the direction of anything you throw into the air. Example: If you throw a ball into the air, the ball will go up into the air and then fall down back to the ground every time. As the ball flies through the air, its movement changes where, at first the ball is moving up, then its direction changes as it starts falling down toward the ground. The ball's direction changes because the gravity force is acting on the ball. Gravity and mass ► All objects have gravity because they all have mass. ► Objects with greater mass exert greater force on objects around them as in the Earth-and-moon system, where: Earth is bigger than the moon and it has more mass so, Earth has stronger gravity than the moon. Also, the gravity of the moon causes the attraction of Earth toward the moon. ► The moon stays in a fixed orbit around Earth due to the gravitational force of Earth. بالتوفيق مستر احمد الباشا