Newton’s Second Law of Motion

Mrs. Border’s Science Class

Essential questionThe size of air resistance force depends on

what two variables?

Newton’s Second LawNewton’s second law of motion connects

force, acceleration, and mass; it explains that an object acted upon by a force will accelerate in the direction of the force; acceleration equals net force divided by mass.

Respectively then we can say,

F= MxA

M

FA

A= accelerationF= ForceM= Mass

Check for understandingSo what is Newton’s 2nd law?

An object acted upon by an unbalanced force will accelerate in the direction of the force according to

M

FA

Newton’s Second LawGravity- attractive force between two objects;

depends on the mass of the objects and the distance between them; gravitational force is also called weight.

The 2nd law explains how to calculate the acceleration of an object if its mass and the forces acting on it are both known.

Newton’s Second LawIn a circular motion, the centripetal force is

always perpendicular to the motion.

Newton’s Second LawThe terminal velocity is reached when the

force of gravity is balanced by air resistance; the size of the air resistance force depends on the shape of an object and its speed.

An object can speed up, slow down, or turn in the direction of the net force when unbalanced forces act on it.

Essential questionThe size of air resistance force depends on

what two variables?

Shape of an object and its speed

Practice problems Remember

1. A net force of 4,500 N acts on a car with a mass of 1,500 kg. What is the acceleration of the car?

2. A book with a mass of 2.0 kg is pushed along a tabel. If the net force on the book is 1.0 N, what is the books acceleration

M

FA