Science Chapter 6 Lessons 4-5

Science Chapter 6 Lessons 4-5

Momentum

The momentum of a moving object can be determined by multiplying the object's mass by its velocity

Momentum = Mass x Velocity

Momentum

If an object's mass is 180kg and its velocity is 16 m/s

Then its Momentum is 2,880 kg m/s

Multiple Choice

An object's mass is 100kg and its velocity is 15 m/s. What is its momentum?

• 1.5 kg m/s

• 150 kg m/s

• 1500 kg m/s

Momentum

The more momentum a moving object has, the harder it is to stop.

Free Fall

When the only force acting on an object is gravity, the object is said to be in free fall.

Free fall is motion where the acceleration is caused by gravity.

Free Fall

Imagine a tennis ball and a crumpled piece of paper being dropped at exactly the same time. If the only force acting on them were gravity, they would fall at exactly the same rate and line up perfectly.

BUT

Air friction is also present. This has a greater effect on the paper's acceleration. So, the tennis ball will fall faster.

What keeps Satellites in Orbit?

• If you throw something horizontally, the object will follow a curved path toward the ground.

  The faster you throw an object, the farther it travels before it lands.

• This explains how satellites, which are objects that orbit around other objects in space, follow a curved path around Earth.

Satellites

• Satellites in orbit around Earth continuously fall toward Earth, but because Earth is curved they travel around it.

• They fall around Earth rather than onto it.

Centripetal Force

A force that causes an object to move in a circular path is a centripetal force

- The word centripetal means "center-seeking"

If you could turn off a centripetal force, inertia would cause the object to fly off in a straight line

- Example: yo-yo