Unit 2 Force Review

Which force do you need push stronger than in order to get an object to start moving?

• Normal Force

• Static Friction

• Kinetic Friction

• Gravity

What does the coefficient of friction ( $\mu$  ) mean?

• It's a measurement of friction for one surface

• It's a measurement of friction between two surfaces, between 0-1

• It's a measurement of friction between two surfaces

• It's actually the force of friction

What are the units of the force of friction?

• No units

• N

• kg

• m/s²

What's the equation for normal force?

• N = mg

• N = m

• N = g

• None of these are correct

A block is sliding across the ground, the coefficient of friction between the ground and the box is .3. The box has a mass of 5 kg, what is the force of friction (must show work on paper and turn in at the end of class)

• .3x5 = 1.5 N

• .3x9.8 = 2.94 N

• 9.8x5 = 49 N

• .3 x 5 x 9.8 = 14.7 N

What is the net force?

• 5 N
• 45 N to the left
• 5 N to the right
• 45 N to the right

Tags

CCSS.HSN.VM.A.3

What is a force?

• the PUSH or PULL on an object 
• The MOTION an object creates
• The objects HITTING one another
• Going REALLY FAST

How can you calculate Net Force? (Mark Both Correct Answers)

•  $\Sigma F\ =\ ma$  

• Adding all of the forces around an object

• Adding the forces in a single line 

• Add the forces in a single line, being careful that some can be negative

An object is falling attached to a parachute. The Parachute provides 300 N of upwards force and Gravity is pulling down on the object with 500 N. Which is the proper way to find Net Force?

• 500 - 300

• 300 - 500

• ma = 300 (500)

An object with a parachute is falling with a positive acceleration of 3 m/s² and it has a mass of 4 kg. What is the correct way finding the Net force on it?

• 4(3)

• 4-3

• 4+3