Forces & Motion, Forces in Action

Forces & Motion, Forces in Action

by Teacher Hanna

​Forces & Motion

• ​Describe the effects of forces on motion, including friction and air resistance

• ​Describe the effect of gravity on object

Multiple Choice

Friction is a force that acts in an ___________ direction of movement.

• similar
• opposite
• parallel
• west

Multiple Choice

How can friction be reduced?

• reduce the force acting between the 2 surfaces
• reduce the roughness of the 2 surfaces coming in contact
• use wax, grease or oil
• all of the above are ways of reducing friction

Multiple Choice

A type of friction that occurs when air pushes against a moving object causing it to decelerate.

• surface area
• air resistance
• velocity
• gravity 

Multiple Select

Which two of these forces act on parachutes?

• Air Resistance

• Gravity

• Thrust

• Kinetic Energy

Multiple Choice

The larger the surface area of the moving object, the ___________ air resistance there is.

• Less

• More

• Longer

• Quicker

Multiple Choice

Air resistance is a force caused by...

• Water pushing against moving objects

• Air pushing against moving objects

• Gravity pushing against moving objects

• Normal force pushing against moving objects

Multiple Choice

Which of the following will change with different gravitational forces?

• mass
• amount of matter in an object
• weight
• kilograms

Multiple Choice

A measure of gravitational force on an object.

• gravity
• weight
• mass
• kilograms

​Measuring Motion

• Define speed, distance and time

• Know how to calculate speed​speed (m/s) = distance / time

• Explain patterns of movement

• ​Able to calculate distance and draw a time graph

​

Multiple Choice

Can distance be negative?

• Yes
• No

Multiple Choice

On a distance vs. time graph, the steeper the slope _____

• the slower the speed
• the faster the speed
• less acceleration
• greater acceleration

Multiple Choice

How far did the object move in 4 seconds?

• 3 m

• 4 m

• 5 m

• 6 m

Multiple Choice

A runner races in the 100 meter dash. It takes him 10 seconds to finish. What is his average speed?

• 10 m/s

• 1000 m/s

• 100 seconds

• 10 seconds

Multiple Choice

How far will a person go if he jogs for 2 hours at a speed of 12 km/hr?

• 6 km

• 0.5 km

• 10 km

• 24 km

Multiple Choice

Which of the following best describes the motion of the squirrel between 5 s and 8 s? 

• The squirrel's speed increased.
• The squirrel's speed decreased.
• The squirrel's speed did not change.
• The squirrel moved backward.

​Forces in action: Density

• Define the concept of density

• Understand how to calculate the density

• Discuss the situation involve density

Multiple Choice

Look at this image.  Which object has the LOWEST density in water? How? 

• The Ping Pong Ball because it floats to the top 
• The bolt because it has sunk to the bottom
• The soda cap because it is not just full of air like the Ping Pong ball

Multiple Choice

What units can be used to express density?

• g/mL
• grams
• millimeters
• milliliters

Multiple Choice

Frank has an eraser. It has a mass of 4g, and a volume of 2cm³. What is its density?

• 8 g/cm³
• 2 g/cm³
• 1/2 g/cm³
• 24 g/cm³

​Force in action: Pressure

Define pressure

Describe pressure in liquid and gases

Multiple Choice

What is the equation used to calculate pressure?

• pressure= force/mass
• pressure =mass/volume
• pressure=area/force
• pressure=force/area

Multiple Choice

What is the unit of measurement for pressure?

• pascal
• grams
• milliters
• meters

Multiple Choice

Pressure decreases when the surface area over which a force is applied increases

• True
• False

Multiple Choice

What pressure does a 4000N horse exert on the ground if each foot is 10cm²?

• 40 N/cm²
• 100 N/cm²
• 400 N/cm²
• 10 N/cm²

​Force in action: Moment

Understand the principle of moments

​Understand how to calculate moment

Multiple Choice

The easiest way to open a heavy door  is by applying the force

• Near the hinges
• In the middle of the door
• At the edge of the door far from the hinges
• At the top of the door

Multiple Choice

A seesaw is unbalanced with two people of different masses sitting equal distances from the center. Which of the following will result in equilibrium?

• The larger person moving further away from the center.
• Moving the smaller person closer to the center.
• Moving the smaller person further from the center.
• Making the larger person do nothing.

Multiple Choice

What is the moment acting on the seesaw?

• 1.6Nm
• 15Nm
• 16N
• 4Nm

Multiple Choice

Assuming the system is in equilibrium, calculate the missing distance d

• 3.4 m

• 2.8 m

• 4.4 m

• 1.6 m