What is force? (In scientific terms)

What types of forces make objects move faster, slower, or stop?

Identify forces of motion

Identify Newton’s laws of motion

Friction and GravityGravity Two factors affect the gravitational attraction between

objects: mass and distance.

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Friction and GravityAir Resistance Falling objects with a greater surface

area experience more air resistance.

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Force that opposes motion

between two surfaces

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Discuss with your partner some examples of things we use to

decrease friction to help objects move easily.

Discuss with your partner some examples of things we use to increase friction to help objects stop moving.

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A speedboat pulls a 55-kg water-skier. The force causes the skier to accelerate at 2.0 m/s².

Calculate the net force that causes this acceleration.

The units of force are newtons (N). The force required to give a 1 kg mass an

acceleration of 1 meter per second squared is one Newton

1N = 1kg x 1m/s2 Go On

Name: _________________

Class: __________________Directions: Follow the steps in the example below to complete the problems.

EXAMPLE:

A speedboat pulls a 55-kg water-skier. The force causes the skier to accelerate at 2.0 m/s2. Calculate the net force that causes this acceleration.

• What information are you given? Mass of the water-skier (m) = 55 kg and Acceleration of the water-skier (a) = 2.0 m/s2

• What quantity are you trying to calculate? The net force (Fnet) = ?

• What formula contains the given quantities and the unknown quantity? a = Fnet/m or Fnet = m x a

• Perform the calculation. Fnet = m x a = 55 kg x 2.0 m/s2

F = 110 kg x m/s2

F = 110 N

1. What is the net force on a 1000-kg object accelerating at 3 m/s2?

2. What net force is needed to accelerate a 25-kg cart at 14 m/s2?

3. What will the rate of acceleration be if a 75 N force is applied to a 25-kg crate?

BEFORE you go on, be sure your worksheet is complete

The Nature of Force

Unbalanced Forces Unbalanced forces acting on an object result in a net

force and cause a change in the object’s motion.

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- The Nature of ForceBalanced Forces Balanced forces acting on an object do not change the object’s motion.

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Forceshttp://www.brainpop.com/science/motionsforcesandtime/force/