๐ŸŽฒ

๐Ÿงช Science ๐Ÿงฒ Forces and motion

Force

The parallelogram of forces is a way to find the resultant of two forces acting on an object. In the right-hand drawing, three children apply two forces to a cart by pulling it with two ropes. In the left-hand drawing, arrows called vectors show the direction and size of the forces. These vectors are used to draw the parallelogram of forces, whose diagonal represents the resultant of the two forces on the cart.
The parallelogram of forces is a way to find the resultant of two forces acting on an object. In the right-hand drawing, three children apply two forces to a cart by pulling it with two ropes. In the left-hand drawing, arrows called vectors show the direction and size of the forces. These vectors are used to draw the parallelogram of forces, whose diagonal represents the resultant of the two forces on the cart.

๐Ÿ“– In short

A force is a push or a pull. When you push a swing, pull a door or kick a ball, you're using a force. A force can make things move, stop them, change their direction or change their shape, like squeezing modeling clay.

๐Ÿคฉ Did you know?

  • There are four basic forces in nature, and the weakest is gravity.
  • Two forces in different directions can be added to make a new force.
  • The heavier an object, the more force it takes to move it.
  • Force is measured with a device called a spring balance.

๐Ÿ”Ž Find out more

๐ŸŒŸ Forces around us

There are lots of forces around us: gravity pulls us toward the Earth, friction slows a rolling ball, a magnet pulls iron, wind pushes sails, and water pushes a boat up so it floats.

๐Ÿ” Friction

When two surfaces rub together, a force appears that resists movement, called friction. It helps us walk without slipping and stop a bike with the brakes. On ice there's little friction, so we slide.

๐Ÿ’ก Balanced forces

In tug of war, if both teams pull equally hard, the rope doesn't move, because the two forces are balanced. If one team pulls harder, the rope moves toward it.

๐ŸŽฏ Measuring force

Scientists measure force in a unit called the โ€œnewtonโ€, after the scientist Isaac Newton, who studied forces and motion.

๐Ÿ“ธ More pictures

The polygon of forces lets physicists analyze three or more forces acting together by drawing the vectors that represent them to form a polygon, and the vector drawn to close the polygon represents the resultant. The analytical method is used to calculate the resultant of a set of forces, based on the idea that any vector can be represented as the resultant of two smaller perpendicular vectors. In the figure above, vector 2 has been represented by forces 2a and 2b.
The polygon of forces lets physicists analyze three or more forces acting together by drawing the vectors that represent them to form a polygon, and the vector drawn to close the polygon represents the resultant. The analytical method is used to calculate the resultant of a set of forces, based on the idea that any vector can be represented as the resultant of two smaller perpendicular vectors. In the figure above, vector 2 has been represented by forces 2a and 2b.
The polygon of forces lets physicists analyze three or more forces acting together by drawing the vectors that represent them to form a polygon, and the vector drawn to close the polygon represents the resultant. The analytical method is used to calculate the resultant of a set of forces, based on the idea that any vector can be represented as the resultant of two smaller perpendicular vectors. In the figure above, vector 2 has been represented by forces 2a and 2b.
The polygon of forces lets physicists analyze three or more forces acting together by drawing the vectors that represent them to form a polygon, and the vector drawn to close the polygon represents the resultant. The analytical method is used to calculate the resultant of a set of forces, based on the idea that any vector can be represented as the resultant of two smaller perpendicular vectors. In the figure above, vector 2 has been represented by forces 2a and 2b.

๐Ÿงฉ Test yourself

1 Which force helps us walk without slipping?

2 What unit is force measured in?

3 Which picture shows โ€œForceโ€?

๐Ÿงช Discover more