Equal and Unequal Forces MGH 172-175

​Different Forces

5.7AB

​Lets Read "Different Forces" pgs.172

Multiple Choice

What are equal forces?

• Forces that cause an object to speed up

• Forces that act together without changing an object’s motion

• Forces that pull objects toward Earth

• Forces that always cause motion

Multiple Choice

Which of the following is an example of unequal forces?

• A boy pushing a wall that doesn’t move

• A book resting on a table

• A boy pushing a box that starts to move

• A magnet sticking to a refrigerator

Multiple Choice

What is gravity?

• A force that pushes objects away from Earth

• A contact force that slows objects down

• A noncontact force that pulls objects toward Earth

• A force that only affects moving objects

​Different Forces

5.7AB

​Lets Read "Different Forces" pgs.173

Multiple Choice

What role does friction play when a ball rolls across grass?

• It speeds up the ball

• It pulls the ball downward

• It stops or slows the ball

• It makes the ball bounce higher

Multiple Choice

What happens when a weightlifter lifts a barbell and the barbell moves upward?

• Gravity is stronger than the lifter’s force

• The forces are equal

• The upward force is greater than gravity

• The barbell has no energy

​Predictable Patterns

5.7AB

​Lets Read "Predictable Patterns" pgs.174

Multiple Choice

What is a predictable pattern of motion?

• A ball rolling in random directions

• A swing moving back and forth regularly

• A car stopping suddenly

• A leaf blowing in the wind

​Energy Transfers

5.7AB

​Lets Read "Energy Transfers" pgs.175

Multiple Choice

What is an energy transfer?

• When energy disappears

• When energy is created from nothing

• When energy moves from one object to another

• When an object stops moving

Multiple Choice

In the illustration, a brick is tied to the end of a rope. Why is the brick not moving?

• The force of gravity is too strong for the brick to move.

• both the force of gravity and the rope pull the brick upward.

• The force of gravity is gone because the brick is held up by the rope

• the force of gravity on the brick is balanced by the upward pull of the rope

​Your TURN...
SHOW WHAT YOU KNOW
STRATEGIES!

Multiple Choice

Observe the chart.

Aida was investigating how forces affect the flight of a paper airplane. The chart shows her paper airplane flight.
Are the forces acting on the airplane in the chart balanced or unbalanced?

• balanced forces, because the height of the airplane is not changing

• balanced forces, because the airplane does not have an engine

• unbalanced forces, because the airplane is in motion above the ground

• unbalanced forces, because gravity is pulling the airplane downward

Multiple Choice

If these boys are pulling with the same amount of force.  What will happen?

• The boy in blue will win.
• They will not move at all.
• The boy in red will win.
• Both will fall down.

Multiple Choice

A class is designing an investigation of how pushing and pulling change the position and motion of an object. Which observations would be most helpful to their experiment?

• A backpack packed with different number of books

• a soccer ball sitting on different types of platforms

• a balloon popped using different tools

• a wagon pulled by people walking at different speeds

Multiple Choice

An engineer wanted to design a floor for a warehouse. Workers in the warehouse would need to push heavy boxes across the floor. The engineer tested four different materials by sliding a box across the surface and measuring the distance it took the box to stop.

Which of the following best explains which material would work best for the warehouse floor?

• The tile because it had the least friction.

• The wood because it would be easiest to push the boxes on.

• The dirt because it has the least friction.

• The asphalt because it has the most friction.